Given that you've already got the NT 4.0 MCSE, you may find the A+ a bit elementary (and perhaps even off-topic) for your needs. The A+ aims to indentify qualified PC technicians who can handle and troubleshoot single-system hardware and software problems at a level of about 6 months of on-the-job experience. Other than forcing you to learn more technical details about modern PCs than you might actually need to know, I'm not sure if this exam will do you much good (since netadmins are usually higher in the food chain than PC technicians anyway).
My advice: stick to the Win2k upgrade for the MCSE instead, unless your job (or future employment) requires lots of hands-on work on PC hardware and low-level configuration stuff.
This was first published in February 2002