Apple has begun placing credit card preauthorization holds for some iPad pre-orders a week ahead of the tablet’s April 3rd launch. While only the Wi-Fi version of the iPad is scheduled for release on the 3rd, some customers that ordered Wi-Fi plus 3G iPad models are saying their credit cards are showing preauthorization holds, too.

Placing preauthorization holds is normal ahead of a product launch to make sure adequate funds are available to cover the purchase before shipping. Since the iPad will be officially available on April 3, Apple will begin shipping units to customers in the next few days.

The iPad is a tablet device with a 9.7-inch multitouch display, built-in Wi-Fi and Bluetooth, and support for most iPhone applications. Users will be able to play music, movies and TV shows on their iPads, and it will serve as an ebook reader, too. Apple will be launching its own ebook store, dubbed the iBookStore, and will be offering its own iBooks ebook reader app.

The iPad is priced starting at US$499 for the 16GB Wi-Fi model.