I jumped in the pool and sank like a rock, I feel like quitting

There are several places that you could look. I am not a swim expert, but it sounds like you could definitely benefit from a coach. Proper technique is absolutely crucial to swimming. There are some very good article right here on BT under the "Articles" section. Also, many people have benefited from the Total Immersion method. http://www.triswimcoach.com  is also a great resource.

As Jimmy Valvano said, "Don't give up...don't ever give up."

Good luck.

A few thoughts.

Use a pull buoy for the interim. This will keep your legs afloat so you can work on your stroke and the rest of your form.

Your wetsuit will compensate for your lack of form during your race (assuming you are wearing a wetsuit for that). It's impossible for your legs to drop when wearing a wetsuit. It will throw your legs/hips high on the water. So, you can rest easy for now, your race won't be a disaster.

Dropping legs is not the result of poor stroke. It sounds like your problem is that you are dropping your hips; dropping legs always follow dropping hips. You raise your hips (and your legs follow) by engaging your abs/core.

Try working on aligning your legs with your body. A good old fashioned drill for this is kicking. Extend a kick board out in front of you and elongate your body. Keep the body extended and engaged. Feel your kick power coming from way high up near your pelvis. The idea is that the power is coming from your core and your legs are merely the delivery system.

I did 800 yards of kick drills tonight and just sailed through the freestyle intervals that followed. Kick drills have a way of engaging your core that can give you immediate rewards and develop good muscle memory for balancing your body in a horizontal position, i.e. your legs won't drop.

I feel your pain.  when I got in the pool 4 years ago I was a disaster.  Used my 8 and under stroke and was gased after 25 yards.  I felt like a mile was never possible.

 I talked to a friend and he reccomended a book "total immersion".  I read that book, did some of the drills, and within about 5 weeks I could hop in the pool and swim a mile no problem.  even did 2 miles a few times.  Try the book, try the drills, get your balance in the water, and things will come along easy.

 Don't give up with a bad start.  I guarantee, with some effort, you can get it down and feel comfortable in the water.

 Good luck! and keep you head down.

In my opinion, swimming seems to be the most technical of the three sports done in triathlon. I recommend getting a coach, looking into Total Immersion or some other type of instructional method. Personally, I'm a fan of swimming with someone else that is or was a competitive swimmer because they can see my stroke and critique my technique.

Anecdotally, I come from a fairly similar athletic background as you (I didn't play college sports but was recruited to, long story, and as a 5'10" guard could dunk pretty handily with two hands, yes I'm fairly proud of that ) and swimming took me quite a while to pick up because I was too stubborn to do it on my own. I finally took a swim class as an undergrad and things clicked. I skipped the sprint distances and upgraded all my races for the summer to olys. So, I say suck it up, get a coach or a training partner and go for it.

Well ... I don't mean to be indelicate but according to your logs, you've done appallingly little swimming this year. How about start with putting in the laps?

You aren't going to get better at swimming by not swimming. SWIM! And do kick drills.

I have coached loads of adults with the "sinker" trait. You will be happy to know that their are solutions. The tough part is that there are several complex causes, and while the forums might give you some ideas, you really need to get to a coach. Most "sinkers" suffer from multiple body position, water comfort and technique issues. Partial solutions can leave you working harder than you should, so get the "whole stroke" approach from a coach who has seen you swim.

Be patient and relax and it will come.

Since you wife has done a Ironman, she obviously knows how to swim.  Can you look at your stroke/form and help?  If not, a coach is probably in order.  I took 4 private lessons from a well known and certified tri coach and it did wonders for me. 

Think of you head as a cantalever.  Be sure your face is down in the water and you are looking straight down to the bottom of the pool then when you breath, try your best to rotate and breath rather than lift your head and breath. 

I too would use a pull bouy in the mean time so you keep building your swim fitness.

I say absolutely, a coach could help.  It is not to coach you on a training plan but to help you with your form/stroke.  A few lessons could have a huge impact.

Don't stop - keep swimming (I try to do 4 days a week, usually manage 2-3).  Use the pull buoy once a week to get a feel for that neutral position.

In January, it took me almost 3 minutes to swim 100 yards in a pool, and I had to rest between sets.  Now I can swim over 1000 yards and average close to 2 minutes per 100 (and I still really suck in the water).  You CAN do it, just keep after it and don't let the slowness of improvement discourage you.

You could see immediate gains if someone tweaked your form in just 1 or 2 ways. Doesn't take 7 weeks to improve form, though you'll want that time to improve endurance.

I don't think you've put enough time in the pool to warrant being discouraged. Keep at it!

Have you asked your wife to look at your form?

Dude, I was so there 8 weeks ago. I couldn't swim a length without dying for air, and my legs sank like rocks.

Today I did my personal best of swimming 935 yards nonstop. WOO HOO!

Get this Total Immersion book: http://www.amazon.com/gp/product/1931009074and practice the balance drills.

If you want, you also can get the DVD that complements the book and gives a bit more details on the drills (I would not go the DVD-only, route, though, the book is essential) http://www.amazon.com/gp/product/1931009074

You'lllearn that swimming efficiency comes from working with the water to achieve balance (e.g., "leaning on your lungs" to help keep your hips and legs up), instead of fighting it.