An enterprising coder has already written a Google Wave add-on for the Firefox browser. (Now if only you had your Wave invite.)
For those of you lucky enough to be Waving already, you can download the extension here. Sure, it's only a Firefox add-on, but for Wave to catch on, users will need ultra-convenient ways of being notified of Waves, or they'll simply stick to the same old rote services—Gmail, IM—that they're accustomed to. That said, the fact that Wave already seems to work on the iPhone Safari browser should also help.
If you're looking to have your mind blown, you might want to temper your expectations; the Wave add-on is a simple notifier that tells you how many untouched waves sit in your inbox. Clicking on it does nothing, but you do have all the glory of the fancy Wave logo in your browser.
The add-on is only compatible with Firefox 3.5.x so far, but you can follow the developer on Twitter to be apprised of other updates.