There is a crazy lot of stuff on web already on details of how to build micromouse. There is no point writing and re-writing it. Below are few good links. For details regarding my project, contact me.
Hardware: I got most of my stuff from here. Not very good but cheep :) http://triindia.co.in/
Events: Just google once. There are techfests/ robotic events throughout the year, all around the word.