A few ways you could do this........

A Merge/Merge Join transformation (http://msdn.microsoft.com/en-us/library/ms141775.aspx)

A Lookup transformation (http://msdn.microsoft.com/en-gb/library/ms141821.aspx)

Do the join in SQL in your source.

The first two would require duplication of your efforts (i.e. more than one of each transform) whereas the third would be pretty easy if you are familiar with SQL. In fact, stay away from the merge transformations if at all possible as they are pretty bad in terms of performance.