Cannot figure out the swim.

Luby you sound like yoru in the same boat as me.  Never been a runner, biker or swimmer. I'm on a 10 week trianing plan 3 weeks in.  First time swimming i got about 25 Yards and died, actually did this for about the first week.  i can strong out 100 yards now "non-stop"  My works out I try and atleast do 500 yards, but after the initial 100 i'm only doing sets of 50 and some times 25 but then have to rest.  Its getting better slowly but surely.

Beginning of this week it took me 17:31 to swim 500 yards, this included resting, and then yesterday i got it down to 16:28 so i'm hoping I keep improving.

One thing I did try that really seemed to help was bi-lateral breathing (breathing from both sides)

You really should probably take a lesson or two.  I guess I'd look in the phone book, maybe ask around at the gym.  Or, find a local kids swim team, go up to the coach and ask if they'd like to make some quick extra money.

Then, when you got the basics, keep it slow and steady to start building that endurance up.  You'll get there.

First of all, congrats on your weight loss to date, and congrats for setting a goal and sticking to it!

A lot of people find swimming the hardest sport to master, especially coming to triathlon without a background in it.  Search the forums, there are a lot of good tips for swimmers having trouble with breathing (in fact, I think there was just a thread about that yesterday).  

I just started swimming laps this year, too.  The first time I got into the pool (I think in April), I could not even swim 25 meters freestyle without choking on pool water and drowning myself  It was a big shock, because I love recreational swimming (ocean, lakes, etc.) and truly thought that this would be the EASIEST part of the sport!  But, sadly, that was not the case.  However, if you just keep swimming and keep on trying, you will improve really quickly.  Now I can swim 1000+ meters without stopping or changing stroke.  

What worked best for me was to swim slowly and practice bilateral breathing (breathe every 3 strokes, so you breathe on both sides equally).  Whenever your face is in the water, you should be exhaling.  Whenever your face is out of the water, don't do anything except inhale.  I use both my nose and my mouth to breathe in and out -- sometimes I do end up drinking some tasty pool water, but it's all good, right?   When you get more confident with the breathing, you can work on refining your technique and speed.

A swim coach and/or swim lessons would not be a bad idea.  Usually you can find adult swimming lessons at the local YMCA for a reasonable price -- that's what I'm doing right now.  When you get more confident in the water and want to get faster, signing up for a masters' swim class would not be a bad idea.  But you definitely need from one-on-one lessons first; otherwise, you will have trouble keeping up with the class (which is frustrating and discouraging).