There’s a Google Chrome extension called Proxlet that gives you a ton of control over what shows up in your Twitter feed.
You can block tweets from certain users, applications, and annoying hash tags.
Even though this is a Chrome-only extension, your settings will still apply to third party apps like TweetDeck or Twitter for iPhone.
We tried out Proxlet and it worked great. It integrates seamlessly with Twitter (make sure you have New Twitter enabled) and gives you options to block users for a set time frame.
To get started, open Chrome and download the extension here. Then head to Twitter.com and log in.