Hey, let's not forget about this free little gem here:

http://www.8052.com/forum/read.phtml?id=34017&top=

You want something more modern, you say? I have used the Nohau already recommended and have more recently had an opportunity to use a Phyton PICE-51 and was quite happy with that. They are about half the price of Nohau without giving up any significant functionality in comparison that I can recall. You can even buy one at a 10% discount right here on the 8052.com Online Store!