XP Product Codes

Here's a list of Product Codes. This is the first number of the Product ID.

55274 : XP Pro generic OEM or Volume License (VL is a special case of OEM)
55276 : XP Pro (upgrade) 
55276 : XP Home (?) '  
55277 : XP Home generic OEM 
55285 : XP Pro '  
55661 : XP Pro (retail) 
76475 : XP Home (upgrade) (?)
76477 : XP Home Royalty OEM
76487 : XP Media Center Edition 2005 
76487 : XP Pro Royalty OEM
76487 : XP Pro volume license (with '640' channel ID) 
76500 : XP MCE 2005 (XP Pro with AD/GPO disabled) 
76588 : XP Pro x64 OEM 

The second number is Channel ID

000 : Other (includes some retail, upgrade and evaluation versions) 
007 : Retail
009 : Not for resale - bundle 
011 : XP Home Upgrade
OEM : OEM (This does not specify royalty or normal OEM) 
270 : Volume License 
296 : MSDN 
308/347 : Microsoft Action Pack subscription 
335 : Retail 
640 through 648, 652 : Volume License (usually generated via 270 CID in setupp.ini) 
699 : Volume Windows XP Tablet Edition 
071 : Possible, but unknown. Possibly an SP2 integrated install of some variety.