Here's the link to Microsoft: http://www.microsoft.com/technet/security/Bulletin/MS08-067.mspx
Creds to the author of the script! Chances are you wont find many systems with this not patched these days. While other MS OS's are affected by this vulnerability, this script doesn't apply to them.
The Shell Script: http://milw0rm.org/exploits/7132
You will also need to download and install the following
Impacket : http://oss.coresecurity.com/projects/impacket.html
PyCrypto : http://www.amk.ca/python/code/crypto.html
Once you have identified a target download the shell script and save it out as a exploit.sh file. Chmod the file for execution.
./exploit *Target IP* *OS*
For *OS* use 1 for 2000 and 2 for 2003 server
./exploit 192.168.0.100 1
./exploit 192.168.0.100 2
Once the Exploit is successfull, telnet to port 4444 on your target, this will place you in a windows shell.
Add your administative user!
You now have root.