The following is from a post I did in August, 2006, and I felt it was important to have it as a valid, available resource. It is CRUCIAL when installing Windows XP under Boot Camp that you use an install disc that really, honest and for truly DOES include SP2-otherwise Boot Camp's drivers WILL NOT WORK, and you'll be stuck with an expensive, nonfunctional PC with great styling.
In other words, THIS IS IMPORTANT.
If you can read the hologram on the disc, you can get a good idea of whether or not it has SP2 by seeing if it reads "Version 2002". This indicates SP1 but not SP2. Bit of it doesn't have SP2, not all is lost! You can, using a Windows computer, create an installation disc that includes SP2 from ANY Windows XP installation disc. It's a process called "slipstreaming," and there's a tacked thread in this forum about it. It really is quick and easy-well relatively quick anyway.
More info here. If you can mount the CD, you can check its version in a text file on the disc. It's called "eula.txt", and it's found in the I386 folder of the install disc. Here's a list of what you'll see in the LAST LINE of the file and what it means:
Windows XP Home Retail
Windows XP SP1 Home Retail
Windows XP SP2 Home Retail
Windows XP Professional Retail
Windows XP SP 1 Professional Retail
Windows XP SP 2 Professional Retail
Windows XP Media Center 2005 Retail
Windows XP 64-Bit Retail
Substitute OEM for RTL for OEM versions.
(Thanks to Wesley Vogel and this discussion board thread
for the details.)
One more detail: a slipstreamed XP install disc will retain the ORIGNIAL disc's EULA, so you won't be able to tell this way. But since it's been locally produced, I'd HOPE that whoever made the disc would label it properly!