Now that you are eager to use your newly acquired knowledge to add utilities and other goodies to your system, you may find them online at the Linux Applications and Utilities Page, or on one of the very reasonably priced CD ROM archives by Red Hat, InfoMagic, Linux Systems Labs, Cheap Bytes, and others.
A comprehensive repository of source code is the comp sources UNIX archive.
Much UNIX source code is posted on the alt.sources newsgroup. If you are looking for particular source code packages, you may post on the related alt.sources.wanted newsgroup. Another good place to check is the comp.os.linux.announce newsgroup. To get on the Unix sources mailing list, send a subscribe message there.
Archives for the alt.sources newsgroup are at the following ftp sites: