SoBig: What You Need to Know
If you or someone you know (or on your network) is infected, here's the manual process for recovering and for preventing SoBig from spreading to other users:

Unplug your computer from the network.
Boot the computer, then hit the F8 key to activate the text-only boot menu; choose Safe mode.
Wait until the boot process completes.
Open Task Manager by pressing Ctrl+Alt+Del and select the Processes tab.
Find and Highlight Winppr32.exe in the Processes tab.
To kill Winppr32.exe, click the End Process button at the bottom of the Processes tab window.
Click the Start button and select Find or Search from the menu. Search All files and Folders for the file Winppr32.exe on all local drives.
Delete all files named Winppr32.exe from the search window.
Repeat steps 7 and 8 for this file Winstt32.dat
Repeat steps 7 and 8 for this file: Winstf32.dll
Got to the Start menu, select Run and type in RegEdit to run the Registry Editor.
From the menu, select Edit/Find to search for this string: WINPPR32.EXE /sinc. Check only the Data box.
Select the Registry Key in the right-hand pane and Edit/Delete from the menu.
Press F3 to find and delete additional keys with values containing WINPPR32.EXE /sinc
Close Registry Editor.
Reboot in normal mode and reconnect to the network.
Install an antivirus and update to the latest antivirus definitions.
Make sure you have firewall software running, because part of SoBig's job is to connect to its master server and try to install a program that would create a back door into your system.
If you have not yet been infected, follow steps 17 and 18 and add these simple rules

Run Outlook with the preview pane closed. Visually scan the subject lines and look for red flags like:
"Details"
"Thank You"
"A Wicked Screen Saver"
SoBig e-mails can come from friends, because you're likely on each other's contact lists in Outlook. If you see an e-mail from a contact that's unexpected or has a telltale subject line, do not open or respond to it.
Never open any attachment from an unknown sender, and think twice before opening unexpected ones from friends or business contacts.
There's some more excellent information as well as removal instructions and even cleaning tools at these sources:

University of Virginia: http://www.itc.virginia.edu/desktop/virus/results.php3?virusID=76
NAI: http://vil.nai.com/vil/content/Print100561.htm
Symantec: http://www.symantec.com/avcenter/venc/data/w32.sobig.f@mm.html#removalinstructions
TrendMicro: http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM_SOBIG.F
TrendMicro: http://www.trendmicro.com/vinfo/virusencyclo/default5.asp?VName=WORM_SOBIG.F&VSect=T
BitDefender: http://www.bitdefender.com/html/virusinfo.php?menu_id=1&v_id=152
McAfee: http://msn.mcafee.com/virusInfo/default.asp?id=description&virus_k=100561&affid=102
Central Command: http://www.centralcommand.com

http://www.pcmag.com/print_article/0,3048,a=55015,00.asp