Chafing in an un-fun area...

If you're wearing drawers under your bike shorts, STOP.

In my order of preference:

Assos Chamois Cream
http://www.rei.com/product/723140?cm_mmc=cse_froogle-_-datafeed-_-p...
EXCELLENT! You can find it cheaper than REI, though. I wear this stuff over 50 miles. It doesn't wear off and it's got medication in it that helps you not get saddle sores. Can't say enough good stuff about it.

Udderly Smooth Udder Cream
http://coachlevi.com/product-reviews/udderly-smooth-udder-chamois-c...
Nice, cheap! I use it whenever I'm going about 50 miles or less.

Chamois Butt’r
http://www.ems.com/catalog/product_detail_square.jsp?PRODUCT<>prd_i...
Available everywhere bikes are sold, it seems. I sweat it off quickly, though, and will use it as a last resort.

Body glide is great for wetsuit points and keeping your feet blister free but I don't like it much for the -er- undercarriage.

Daniel gave some really good recommendations.  Assos is my favorite, too.

Another cheap product you can use is Bordeaux's Butt Paste.  It's usually in the baby section of stores like Target with the diaper rash cream, but I've used it instead of chamois butter or Assos in a pinch and it works fine.

I use Brave Soldier Friction Zone...that seems to do ok for my skin.  I hear the guys like dznuts high viscosity chamois cream.

Target brand diaper rash cream, works great, and it's cheap and readily available.

Assos Chamois cream! Seriously the best stuff ever and will prevent chafing problems in the future and actually help you heal the problems you have now.

Another great tip, Assos works really well on you feet as well to keep them nice a cool during the hot summers or will keep them happy during a marathon... Feels funny at first, but it works great!

I use neosporin (sp?) on a current rash, and take a day off from riding; and a day off from running in tri shorts. Its usually cleared up in 1-2 days.

I also use body glide, apply on skin, and on the seams of your shorts.

Gold bond medicated powder helps with existing stuff. Burns a little at first if its severe and makes you smell like a medicine cabinet. Very affective though.

Chamois Butt’r
http://www.ems.com/catalog/product_detail_square.jsp?PRODUCT<>prd_i...
Available everywhere bikes are sold, it seems. I sweat it off quickly, though, and will use it as a last resort.

I second the above. I used it for a century ride two weeks ago and it worked great. I sweat a lot and I did not have to apply a second application (but I put on a generous amount to begin with).

Hope you don't mind me tacking onto this thread but, a closely related question:  For those of you who do Iron distance races in Tri-shorts, can you still use Assos or the other above recommended products? Doesn't the swim before pretty much wash it away before you even get on the bike?  Does it work with the thin cloth pad of shorts like my DeSoto Forza's?

Thanks for any advice.