I bought the OEM of WinXP Pro just last week. It installed fine. I do not think that there is any difference in the install between the OEM and the full retail version. It came with some sort of little booklet, but I didn't open it but it isn't big enough to be much of a manual. Would offer a description but it looks like it up and walked away. Just inserted the disc, told it which drive to install on and updated drivers when it was done. Not too difficult. The longest part of the whole thing was converting the "almost" new drive to ntfs.
Oh yeah, and you can probably get that cheaper on the web. Not sure what Newegg or Mwave are charging, but you only need to buy something as expensive as a ten cent case screw in order to be able to purchase the OEM copy.