I leased my home to three roommates (1 yr. lease). Two pay their rent on time. One moved in a month before the others, and I was being nice when I didn't charge him for the extra month. He moved out after 7 months without giving notice. He left all his furniture and clothing at the house in his room. The other tenants don't know where he lives, but said he drops by once in awhile to get his mail from the mailbox, which has a lock box. He has to use his mailbox key to get the mail. It's difficult to show the room to potential renters because all his stuff is in the room. He won't return my phonecalls, and hasn't paid his share of the rent in more than two months. Can I store his belongings and send him a bill for the cost of storage, the movers fees, and the moving truck? Do I have to serve him with a 3-day notice at my home since I don't have another address for him??
Help!! The lease agreement clearly states his responsibility if the lease is broken.

See this neat flow chart: ExpressEvictions.com California Eviction Flowchart
Procedural rules, like the 3 day notice, are like hoops that you must be able to demonstrate to the court that you have jumped through, so send the letter registered mail, and when it is returned to you, make it a part of your file.

Yes, this is one of the options. You can get one from:

http://www.landlordevictionnotice.com/california-eviction-notice.htm

Hope this helps.