Many specifications for the Internet are published as so-called "requests for comments" or "Internet drafts". They can be browsed and searched via www.rfc-editor.org and www.ietf.org. I've collected some RFCs here in the hope that you need not search as long as I did. :-)

HTTP

HTTP/1.0 protocol: RFC1945
HTTP/1.1 protocol: RFC2616 (errata)
HTTP version numbering: RFC2145
HTTP authentication: RFC2617
HTTP extension framework: RFC2774
HTTP state management mechanism ("cookies"): RFC2965 (practice: RFC2964)

FTP

FTP: RFC959
FTP security extensions (the commands "AUTH", "PROT" etc.): RFC2228
FTP extension for IPv6 and NATs (the commands "EPRT" and "EPSV"): RFC2428
FTP security considerations ("bounce attack" with proxies; password guessing): RFC2577
Firewall-friendly FTP: RFC1579
FTP feature negotiation (the commands "FEAT" and "OPTS"): RFC2389
FTP i18n: RFC2640
FTP extensions (draft #16, expires March 2003; the commands "MLSD", "MLST", "SIZE" etc.)

TLS/SSL

TLS: RFC2246
HTTP over TLS: RFC2818
HTTP/1.1 upgrade to TLS: RFC2817
Securing FTP with TLS (draft #10, expires 2nd April, 2003)
HMAC hashing: RFC2104
TLS extensions (draft #5, expires January 30, 2003)
SSL 3.0 (draft #2)

Miscellaneous

Requirements for Internet hosts: RFC1123 (updated by RFC1349 and RFC2181)
URIs: RFC2396 (report: RFC3305)
Base64 encoding: RFC2045, 6.8
Finger: RFC1288
Gopher: RFC1436
HTML 4.01 (errata)
CGI (Common Gateway Interface)
NNTP: RFC977 (extensions: RFC2980)
JavaScript (experimental proposal 2.0)
IPv6: RFC2460 (addressing: RFC2373; basic socket interface extensions: RFC2553; advanced API: RFC2292)
Internet Message Format: RFC2822 (IMAP4: RFC2060; POP3: RFC1939, RFC2449)
RFC errata
User Agent Accessibility Guidelines