Here at UMDNJ, a limited collection of such files and documents are archived at the UMDNJ Remote Access archive. At digex.net, you can find information on Internet Access Using SLIP or PPP, and at Yale University, you can find the PC Lube & Tune Exit Ramp.
For Macintosh users, there's the Internet resources for the Macintosh page at the University of Washington, as well as Rutgers' web pages on Connecting to RUNet using SLIP on a Macintosh.
For PC users, an invaluable source is the Trumpet Winsock Installation pages. The Windows and TCP/IP for Internet Access web page is maintained at the University of Vermont, while you can find a comprehensive Glossary of Internet Terms at matisse.net. Additionally, the Internet Documentation (RFC's, FYI's, etc.) defines the foundations of the Internet and its bleeding edges.
There are several Usenet news groups related to Remote Access. Representative of these are the comp.protocols.tcp-ip newsgroup, the comp.protocols.tcp-ip.ibmpc newsgroup, and the alt.winsock newsgroup. Modem information can be found in comp.dcom.modems
A frequent and integral consequence of active newsgroups are Frequently Asked Questions lists. These lists are required reading if you want to stay on top of this material. For example, if you are interested in PPP, you will want to read the comp.protocols.ppp FAQ list. The alt.winsock FAQ list can be thought of as the living documentation and troubleshooting guide for Windows PC's on the Internet. Similarly, the Winsock Application FAQ is essential reading for users of Winsock applications. A recent addition is John Navas' list of Frequently Asked Questions on 28.8kbps modems. Note that this FAQ tilts heavily towards USRobotics modems.
A quicky guide to Very Useful Stuff is found at comp.protocols.tcp-ip.ibmpc Frequently Asked Questions (FAQ), part 2. A more narrowly defined site at the NCSA provides all you'll want to know about NCSA PC Telnet.
Mail lists, or so called listservs, also provide ongoing current information, and often the mail and related files are archived, such as at the Winsock-L Home Page.
As you might imagine, there is an enormous amount of information available on Windows Sockets applications, as can be seen at The Consummate Winsock Apps List, the Winsock Applications and Resources, and the eznet winsock directory.