Tweet Ups are very much happening right now. One of the main parts of organizing a Tweet Ups is to invite people. To simplify this here is a small event manager for Twitter. It is called twtvite, an easy way to use Twitter or Facebook to create a micro-invite for your friends and followers. You create an invite on the twtvite site, and then micro-message with a tiny URL on Twitter or Facebook. The link takes people back to the site where they can RSVP.
By using Twitvite you can Create an event, enter the location, date, time, your 140 chars description, and share it/ manage RSVPs. This makes the whole process of creating tweetups so simple. You can follow me from here.. http://twitter.com/pcsbox.