mr. plow,
Check out [HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList]
key. You will see all the SIDs there.
Also, if you load a user profile - you will see the SID assigned.
Another way - GetTokenInformation API.
Also, IIRC, newsid.exe from sysinternals.com has an option to show current
SID. But I don't remember this exactly.
KM