Avast! Browser cleaner (free stand alone download) seems to be effective against those things. Caution when installing free software (often trying to slip through Google chrome, ask taskbars and whatnot) should be you first line of defence but the odd thing I had slip through was effectively removed by avast! Spybot deals well with some of the more malicious ones (babylon can be a pain in the neck for example but spybot manages to you rid from that one well).