Oh, I don't even mind sharing here. I just didn't want to blab on about it if nobody was interested anymore... or miss your post if I wasn't on for a while!
There are probably a dozen sites that offer this service, but I'll share the ones I used and my thoughts
wiialerts.org is an incredibly nice site. They have lots of options available for which stores you'd like to track, various ways to be alerted (email, pop up on your screen, text, etc). I get several alerts from them per day (at first I was including searches for bundles that included wii fit, not just the game), and they have always been accurate. When you get an alert, you go to their site (there aren't details in the text, it's just a standard message every time) and there will be a link on the first page that is directly to the product you were referred to, if that makes sense. They also have sort of 'reviews' on what sites are notorious for canceling orders or give "false alarms" (say they're in stock but NOBODY reports seeing it as such), etc.
That being said, I ended up scoring the Wii fit with findoos.com. It doesn't look like much, and I think that's why it works

I read somewhere that they have fewer subscribers, etc so the texts go out more quickly. In this instance anyway, I can vouch for that. I got the text from that site, got the Wii Fit, and it was sold out almost immediately. After it was gone, I got alerts from the other site, and the email from findoos.com.
The other one site that seemed to update in fairly real time was nowinstock.net
I hope that helps! Like I said, it only took 1.5 days from when we decided to buy to get one (hopefully, assuming it comes

). Of course, had I not been on the computer at the time it would have been different, so there is certainly some luck to it... but it appears that, for now anyway, something like this is better than sheer dumb luck!
ETA: These sites are all free, but of course they will remind you (as will I) that 'standard messaging rates may apply'
Thanks!