Apple iPod touch iOS 2.2 - Manual (Page 53)

Chapter 4 iTunes and App Store 53
You must be signed in to your iTunes Store account. If “View My Account” doesn’t
appear in the Store menu, choose Store > Sign in.
Purchase music or applications from another iTunes Store account: Sign in to that
account when you connect to the iTunes Wi-Fi Music Store or when you purchase or
download an application from the App Store.