For my jeep I usually use like car wash soap on the top when i wash the body. Then when I am finished I apply like black magic tire/wet to the top with a sponge. The tire wet has a UV protectant in it that helps keep my top nice and black. It also gives it a nice deep black sheen I definately reccomend it on the top, I've been using it on my top for 3 years now and seen only good rusults.
For the plastic windows don't use windex or anything with ammonia in it. Someone in a forum on this website suggested furniture polish, I don't remember what kind though.
I bought this stuff off ebay for 6$ shipped that worked real nice
http://www.4bangerjp.com/forums/viewtopic.php?t=1237here is link to that forum