Getting help with Linux
When you are in the market for a CD-ROM, make sure that you are getting a recent distribution; these can be obtained from many vendors, such as Cheap Bytes, Prime Time Freeware and Linux System Labs, often for as little as a few dollars. Be wary of older CD-ROMs; using older versions of the software may be more trouble than they're worth - the active and continual development of the Linux system means that the software on old CD-ROMs will be significantly different from the bleeding edge Linux that's out in the field. Since Linux is constantly getting easier to install and use and hardware compatibilities are always being added, you will save yourself some grief by installing from the newest version you can get.
On that note, be careful of the publication date on any books you might be considering. As a rule, any technical book or CD is outdated to some degree upon publication. It is generally safe to assume that any Linux book or CD over a year and a half old is hopelessly out of date. Furthermore, if you find a Linux book or CD more than three years old, consider it an object of Internet and computing antiquity (maybe keep it for historical purposes or as a conversation piece).
When it comes to applied computing - and specifically the Internet/UNIX world - the books published by O'Reilly & Associates seem to be without peer. Their TCP/IP Network Administration by Craig Hunt is a must-have for learning the basics of Internet networking, and they've done the same with their selection of fine books on Linux. The latest edition of their book Running Linux, by Matt Welsh and Lar Kaufman, is perhaps the finest all-around general-purpose Linux overview currently available.
The Free Software Foundation also publishes many books documenting free software, including the GNU manuals, the FSF's books are as free as the software they write about, and buying these books is a good way to show support for this organization.