MacRumors.com

Apple is sending out emails to those with iPod Mini pre-orders, offering to provide a 15GB iPod instead of an iPod mini for those interested.

Dear Apple Customer,

  Thank you for ordering the new iPod mini!

  The demand for the iPod mini has been incredible. We are shipping them as
  quickly as possible, but we cannot meet the ship date we previously estimated
  for you. We now expect to ship your iPod mini in three weeks. If we do not
  hear from you prior to shipment, we will assume the revised date is
  acceptable, and will ship your order. We apologize for any inconvenience.

  Your business is very important.  If you would like an iPod sooner, we are
  offering to replace your iPod mini with a 15GB iPod at no additional charge.
  This model usually ships within 24 hours. Taking advantage of this offer is
  easy:

  By email:  Forward this note to customerconfirm@apple.com and check the option
  below.
  ____  Please switch my order from the iPod mini to the 15GB iPod at no
  additional charge.  My order number is ______________.

The 15GB iPod retails for $50 more than the iPod Mini.