some here like them if you dont and want rid of them heres a way to really help
use the following plugins
akismet - tried and tested and used by most wp bloggers
Spammer Blocker - works whenever you spam a comment
TTC Security Plugin - bad bots list - remember to update list
also
Visitor Maps and Who's Online plugin
can be used to get a list of bots and ips easily from wp admin side
hope this helps