1.For user defined function one must have to specify it's 
return type while in stored procedure it is not mandatory.

2. u can use function in expression but not stored 
procedures

1. Stored Procedure to return the output parameter.
    but function only return single values no output 
parameter.

2. Select Clause we cann't use stored procdure. but 
fucntion we can use.

3. XMl Clause contain we can use stored procdure. but 
function we cann't use.

4. Whenever to execute function at present any error in the 
function automatically to exit from the function. but 
stored procudure to ignore the error then go to next line.

By
Kumar.T