Other World Computing (OWC) has released over 50 Do-It-Yourself (DIY) Storage Upgrade Kits for laptops and Mac minis.

Manufacturer's suggested retail pricing starts at US$67.99 for a model that consists of a 2.5-inch SATA hard drive up to 1TB, an OWC brand FireWire and/or USB 2.0 bus powered 2.5-inch portable external enclosure, and a five piece installation tool kit.
With an OWC DIY Storage Upgrade Kit, Mac and PC notebook users and Mac mini users can upgrade their computer's internal hard drive to a new larger capacity and/or faster speed, transfer their data to the new drive, and then continue using the "old" drive by installing it into the provided OWC enclosure for a "new" pocket-sized external drive at savings of up to 40% versus buying all the included components separately. For more info go to http://www.macsales.com/laptopdiy .