Ohh looks fun! How warm do you think the water will be??
I can't really give you wetsuit advice, as it took me 5+ suits to FINALLY find one I liked! Actually I have the same kind Lise does- a short john, but I got a long john for IMAZ and am in the process of ordering the long sleeve model of my long john from Trisports.
Goodluck w/ your search! It's ohh so fun... (insert sarcastic tone)...
Oh- check out the last two reasons to do an IM on this (page 3 I think)

http://www.xtri.com/article.asp?id=434

Yes, you CAN do it!! If I can do it, ANYONE can!
You see that is the difference between those who TRI and those who Don't. Those who TRI say "I'm not sure if I *can* but I'm gonna tri" those who don't say "I can't do it, so why bother putting myself through it. It might hurt, I can't run, I'm a slow swimmer, I hate those little bike seats, I don't like to sweat etc etc"... I've heard it ALL!
I always say "If you really WANT it, you can have it. You just have to be willing to do the work".