Then I came across this Blog: Z Report on Plastic Sippy Cups and BPA which has done all of the work for me!  It is an incredibly thorough list of cups and bottles all tested by their 2.5 yr old and researched for cups and bottles containing BPA.  It's also a great site for all things kids, baby and parent friendly that I highly recommend checking out.

Turns out, all of my sons sippy cups are BPA free! This is great for my bank account since some of these cups are quite pricey.  I still think it is a good idea to replace all worn out cups made of any kind of plastic and if you are still concerned about BPA, go for stainless steel (Klean Kanteen).