AOL, ICQ networks to communicate
Considering the history of IM network interoperability, I thought this might never happen; the next version of AOL's Instant Messenger software will be compatible with ICQ's network, allowing users of both IM services to send messages back and forth.
AOL's parent company owns ICQ, so IM service compatibility probably won't extend beyond the two networks. Sorry Microsoft, Yahoo. If you do want all your IM accounts to cooperate with each other, there's still Trillian, which handles ICQ, AIM, Yahoo, and MSN networks. Heck, you can even use it to hang out in our #techreport IRC channel.