You can search the catalog for legislative histories, which can save a lot of time and effort.
Each stage in the legislative process generates documents that may be useful in determining congressional intent. For example, see the following diagram on the federal congressional lawmaking process from Westlaw.
You can't use Wikipedia as a source, but it's useful for gathering background information on a topic and getting references to use. Look at the see also, references, notes, external links, and further reading sections as found in the entries.
Legislative History is the term used to refer to documents generated by a legislative body during the process of passing a bill. It includes bill text, hearings, congressional debates, committee reports, presidential messages, and other documents. Legislative history is used to help interpret statutes if the meaning is ambiguous. The information gathered is usually used to determine the answer to the question: what was the intent of the congress?