For somebody who wants to get a general networking or operating system certification like MCSE, CCNP and so forth, I'd strongly recommend pursuing a small sequence of CompTIA certifications to start.
Begin with the A+, then go for the Network+, then get the i-Net+ (all of these are documented at www.comptia.org). After that, you'll not only have a pretty good general computing and networking background, you'll probably have a much better idea of what kind of certification you wish to pursue as well.
One more thing, you can read a general online book I've written about certification programs at my parent company's web site at www.leapit.com (However, you must sign up as a member to gain access to this book. It is called "Certification Essentials" and appears within the LearnIt area on the site).
This was first published in April 2001