[abrowne]

I've seen a lot of Mac users with adware in the last few months. I've found Adware Medic[1] to remove nearly all of it pretty easily.

[1]:http://www.adwaremedic.com/

[corv]

Seconded, AdwareMedic is quick and painless.

Power users might also appreciate Little Snitch[1] to see what their Mac is connecting to.

[1]: http://www.obdev.at/products/littlesnitch/index.html

[abrowne]

I forgot to mention, after running AdwareMedic, make sure to check browsers' search engine and homepage settings.