Still waiting for its turn to get into the slow-moving App Store, IM+ is ready with version 3.1 which adds support for iPhone 3.0 Push Notifications. Text alerts, badges, and sounds are all supported, and can be individually enabled or disabled both through Apple's Notifications Settings panel.
IM+ supports a ton of services, including Skype, AOL, MSN, Twitter, Facebook, Yahoo!, Google Talk, Jabber, ICQ, and MySpace. Testing it with AOL proved to be a quick, clean experience, with IM+ launching and re-connecting to their server in a brisk and snappy manner on an iPhone 3GS. Copy and Paste also worked well, albeit it only in the text input box (I couldn't find a way to select or copy text from previous chat bubbles).
Hopefully Apple will approve IM+ 3.1 with Push for the App Store soon. In the meantime, you can take advantage of sale pricing on the previous version, 3.0 (which pushed via re-direct to email). $5.99 via iTunes.
More screenshots after the break!