I got an iPod Touch for Christmas and tried to buy an album and did not work as follows. This will be the same on iPhone.

- Click iTunes icon and find an album you want to buy.
- Click the price to change it to buy now and press again
- Album flys down to 'Downloads' and a red/white (1) appears then goes within a second
- Pressing 'Downloads' shows no download in progress

Cause:
Apple want you to accept a terms and conditions screen which is not displayed on the wifi music store

Solution:
- Connect iPod Touch/iPhone to computer and run iTunes and connect to the iTunes store and add an album to your shopping cart

- Go to shopping cart and buy the album.

- Terms and conditions screen appears and accept. A box appears asking to try the purchase again

- Delete album from shopping cart and eject iPod/iPhone.

Downloading via Wifi music store now works!