Sadly for those of us who do legislative history not all bills become laws. Bills that become laws are memorialized in books with copious annotations and references to their histories which make them easy to locate. That is not the fate of most bills. Most bills simply die and accumulate very little if any legislative baggage. Bills that do not become laws die and are forgotten and their burial places are hard to find.
Finding bills online can be easy as in the case of recently filed bills. The Library of Congress’ website THOMAS has full text of all bills filed back to the 101st Congress (1989-1990). There are multiple ways to search for these bills, including by sponsor, number, and keyword. The harder bills to find are those that died before the invention of THOMAS. Trying to find the full text of older bills in electronic format is more difficult and the researcher must get creative.
If you are looking for really old bills the Library of Congress has a website for you. A Century of Lawmaking for a New Nation website has links to House Bills and Resolutions from the 6th thru 42nd Congresses and Senate Bills and Resolutions for the 16th thru the 42 Congresses. Both these websites provide excellent images of the bills, and coincidentally both stop in 1873; the year the Congressional Record began publication.
The next place to look is the Congressional Record. If you have the bill number of the bill you are looking for it might have been read into the Congressional Record. The final volume of the Congressional Record for each session of Congress contains a history of bills and resolutions for each chamber of Congress. These histories provide page numbers for each reference to a particular bill and what action is taken on each page. Not only can you track down the text of a historic bill, but you can also follow its path through the law making process.
Another place is the text of Committee Reports. These are available through the Serial Set found on ProQuest Congressional. While not comprehensive, you might just get lucky if the bill is associated with an important piece of legislation.
The other alternative is to travel. That travel may be to a regional depository library or to Washington D.C. to visit the Library of Congress or the Senate Library. If you can afford it this method is very reliable.
The Law Librarian’s Society of D.C provides an excellent guide for finding full-text bills here.