this is what i use and it works great: "1. sign up on SuperTweet.net and authorize it with your twitter account. 2. open up Keychain Access and make a new entry (just enter SuperTweet as the item name, SuperTweet username, SuperTweet password)
3. edit your current Tweet script to something like shown below (basically changing references from Twitter.com to api.SuperTweet.net). *Bonus tip:* you can hard-code geolocation to your tweet, which is useful if you always Quicksilverly tweet from the same place/s, or if you feel like lying about where you are." you need the script from this link: http://www.jaysintrevino.com/blog/2010/9/30/quicksilver-twitter-and-oauth.html
