Ryan over at Punchkickinteractive is always good for a great post. This time the 5 Commandments of Mobile Web design. Here a quick summary:

1. The Mobile Web is not the little sister of the Traditional web.
2. Give People What they want, when they want it
3. Build unique mobile content, or don’t bother at all.
4. Make it useable (3xtimes)
5. Don’t forget about design. Seriously

and my 6th one:
If you design for mobile, read Ryan’s book (cannot find link now…but read it!).