It's not strictly a 'jersey' but I'd reccommend the white or yellow Canari SPF shirts... VERY light cloth and if you're out or an extended period, the SPF factor may be an added bonus.

Exte Ondo stuff is generally of very high quality, I've found... it *looks* and *feels* very, very nice... but I don't actually own any to really comment...

The Louis Garneau carbon jersey claims to have superior temp management, and to look at it, it's very light, and mostly white... Carbon Ion? I think? I know TE carries it... just not sure of the name atm...

Personally, I'd slap on a TON of sunblock and go for a tri tank with a lot of mesh to it, then just make sure I'm drinking enough that the perspiration and mesh do their respective jobs... i *like* the sugoi tri tanks...