I wanna learn how to code great plugins...

If you'll forgive the outrageous self-promotion, Addison Wesley have
recently released a short PDF book which should help guide you though
what you can do with Rails plugin:

http://www.awprofessional.com/bookstore/product.asp?isbn=0321483510&rl=1

I'll make a bit more of a noise about this once they fix the typo in
my surname :slight_smile:

- James