Chax with Mac OS X Lion?
I've been in communication with the creator of Chax, and no, it doesn't work on Lion (it definitely works in Snow Leopard). He says he's working on it. 

His site is here. 

Addendum 9-11-11: The main awesomeness of Chax is the ability to auto-accept Screen Shares with certain people in your Buddy List... including yourself. For instance, if you travel with a laptop and suddenly need to get files from your Mac back home, you simply get a second iChat/AIM account for that laptop, set up Chax on the home Mac, set it up to autoaccept the laptop's account, and you can screen share automatically with your home Mac. I've come to completely rely on that weekly for the past couple years.