Look around and you'll find things. I've become a real fan of Merino wool in the last few years. I got a couple of the cheap Costco polos, they're OK. Rivendell (of course) has some merino shirts and tights that I like and use regularly. Short sleeve for summer! www.rivbike.com I've bought one or two things from Sierra Trading Post as at least one other post has mentioned.

None of the things I have are actually called bike jerseys, and none have a rear pocket, but other than that they work well for me.