Just installed the apps and they are working fine.
Updates iTunes, then firmware on the Touch, then bought the apps via iTunes, it synced for me after I hit the pay button and entered my login/PW. The first time I tried it crashed and I had to buy them again ( I checked my purchase history before I bought them again and it had no record of the first purchase - hope it stays that way ).
Good luck. The apps seem cool;
Weather is ok, but not really much more convenient than browsing to the weather channel page or something. If I check the weather, I want to know more precisely than the closest large city - which is 40-50 miles away.
Maps seem to be formatted and work better than google maps ( IMO ).
Notes - this is what I was waiting for! ( may not be as good as what's to come via 3rd party, but it's way better than what I had )
Mail - Nice, I use it for my ( low-traffic ) gmail account, it's easier than browsing via Safari, just a 1-touch and you're at your Inbox. I didn't think I would use it, but looks like I will.
Stocks - Cool application, again, one-touch quick access, but lacks details, for me it works, but for someone more into stocks, it won't beat whatever website you frequent for the same info.
For me, Mail and Notes, definitely worth $20, free would have been nice, but $20 is worth it to me.
BH