I'm doing my research and building my website with the intention of becoming a provider this summer.
I have a moderate latex allergy, but polyurethane is...crunchy. I really like the polyisoprene condoms--I think Lifestyles Skyn is the only one out there. They're actually better, sensation-wise than latex, I think. But I've never heard anyone mention them as a viable alternative for providers. Are they sub-par in disease prevention or something?

That's what I always bring, and several ladies that I've seen have had them as well. The one thing I've always wanted to try is the female condom.

Use the search function, and you will find a great deal of information about them.

Jaycee

I was with a lady last year who uses polyisoprene condoms and as a hobbiest, I think they're great!! They fit better than latex and transfer the body warmth better.  It doesn't feel like I'm wearing insulation on my member....
They have been approved by the FDA for disease prevention in Feb 2009, I think.  Just as safe as latex according to them. Do not use oil based lubricants with this condom.  
I switched to them in March 2009 for all my fornicating needs......

Skyns is a good suggestion. I also had a similar question and here is remilively's answer to my post asking for a better tasting alternative to Skyns. You've got to encourage BJ's anyway you can

Beyond Seven, Crown Skinless Skin, & Kimono Micro Thin are all good choices in my experience. I haven't tried Skyns but I bet if you put a dab of flavored lube on them, it would make them taste much better.

On top of that, I also asked the Love Goddess (on the Erotic Highway) a question regarding just that subject - and got a slew of good answers.  

There are actually several brands that are good, despite the "crunchy". PM me if you want.