There are a couple of excellent resources available online.

Screencasts :
http://colinramsay.co.uk/2007/04/17/getting-started-with-monorail-screencast-one/
http://colinramsay.co.uk/2007/04/18/using-monorail-screencast-two/
http://colinramsay.co.uk/2007/04/19/databinding-and-activerecord-screencast-three/

Tutorials:
http://blog.bittercoder.com/PermaLink,guid,b298cbe4-6eff-4783-a2a1-c95e344a9de5.aspx
http://blog.bittercoder.com/PermaLink,guid,195c3d13-faf8-4f5e-8faf-861d02b0fc2e.aspx