Thanks to Key we have httptunnel:
Title: httptunnel.tce
Description: httptunnel creates a bidirectional virtual data connection tunnelled in HTTP requests.
Version: 3.0.5
Author: Lars Brinkhoff
Original-site: http://www.nocrew.org/software/httptunnel.html
Copying-policy: GPL
Size: 17.4k
Extension_by: Key
Comments: The HTTP requests can be sent via an HTTP proxy if so desired. This can be useful
for users behind restrictive firewalls. If WWW access is allowed through a HTTP proxy,
it's possible to use httptunnel and, say, telnet or PPP to connect to a computer
outside the firewall.
Title: httptunnel.tcz
Description: httptunnel creates a bidirectional virtual data connection tunnelled in HTTP requests.
Version: 3.0.5
Author: Lars Brinkhoff
Original-site: http://www.nocrew.org/software/httptunnel.html
Copying-policy: GPL
Size: 382k
Extension_by: Key
Comments: The HTTP requests can be sent via an HTTP proxy if so desired. This can be useful
for users behind restrictive firewalls. If WWW access is allowed through a HTTP proxy,
it's possible to use httptunnel and, say, telnet or PPP to connect to a computer
outside the firewall.