http://www.newegg.com/Store/SubCategory.aspx?SubCategory=92&name=External-Enclosures
That should bring you to external enclosures on newegg.com. use the navigation on the left to find the proper form factor and connection type (sata/ide) and whichever interface you would like (USB 2.0, Firewire, eSATA)
They shouldn't be too expensive, and the reviews on that site are very helpful.
if you need any info on setting it up, the enclosure will probably come with instructions/a cd, and you can always use google to get the basics.