Twitter is making it easier to fight profiles which users feel are spam. When you're on the profile that seems very spammy, just look for the "Report as Spam" option, which is now under the "Block" option on the right-hand sidebar. Previously, Tweeple could report spam by contacting the @spam account set up by Twitter.
When you report a profile as spam, it doesn't automatically suspend an account. That would make the system to game-able. However, if you do report a profile as spam, that account will be blocked from following you or appearing in your Twitter stream.