How to run a litecoin miner behind a proxy server?
I got it working for pool-x.eu connecting via port 80 (the proxy server name and port is just what my browser uses):

@echo off
set HTTP_PROXY=http://myproxyserver:myport
START /LOW /B minerd.exe --algo scrypt --url http://mine.pool-x.eu:80/ --userpass myusername.1:mypassword --threads 4 -r -1 -s 5


Not all pools allow connections through port 80, so it does limit which pools you can connect to.