If you are looking to audit CURD operations on tables. Like if you want to know which columns have been updated and want to know the old values as well, an easy way is to implement Change Data Capture. Here is the link http://msdn.microsoft.com/en-in/library/bb522489(v=sql.105).aspx
In case you have a different requirement. Please do specify.
~ Lokesh Vij
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