you can use trillian. it is an alternit client for icq. it also lets you comunicate with all the other im networks.
http://www.ceruleanstudios.com/downloads/ i use it myself and it works perfectly. and there are no ads. there is a pay version and a free version. i run the free version, if you want wizz bang gizmos go with the pay version, if not get the free one.