I've found that I prefer the new sleek Gmail gadget over the bulky word wrapping iGoogle gadget. You can add it to your iGoogle page by clicking Add stuff », then Add feed or gadget, and then paste the link http://www.rememberthemilk.com/services/modules/gmail/rtm.xml into the Type or paste the URL below: box, and click Add.

Not an earth shattering tip, but I like it :)