The Symantec Security blog has an article titled "Botnets: not just for spamming anymore". Interestingly we are now starting to see the use of botnets for more than just simple spamming (or simpler DoS attacks).
Its pretty cool (in a twisted sort of way), because this is one of those things we called out a long time ago, predicting that botnets were way under-used as a form of cheap distributed computing. We have been mentioning its potential for effectively minimizing the key-space of session-ids and it looks like its starting to rear its head..
Its one of those combination "i expected this a long time ago" && "oh #$@#.. lets hope it doesnt catch" moments..