The limit for a varchar field is 8000, if you use the text datatype you can have 2,147,483,647 characters.
Bear in mind that when you use the text datatype you can't use ordinary string manipulation functions. The text is treated as BLOBs. Have a read of 'BLOBs and OLE Objects' in Books Online.
Hope this helps
Phill Carter
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Colt 45 - the original point and click interface
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Colt 45 - the original point and click interface