Now that you have purchased your new Windows Phone 7, you would want to get all the contacts from your old phone imported to WP7. If you have a GSM based phone, you can copy all contacts from your previous phone to SIM card and then import it to Windows Phone 7.

Insert the SIM and then navigate to Settings-> Applications-> People

Press Import SIM contacts and follow the instructions.

If you have a phone on a CDMA network, you’ll need your mobile operator to help transfer the contacts from your old phone to your new one.