When Squid is installed and running, it uses port 3128 by default. You should test it manually by setting your HTTP proxy to the server that runs Squid. For instance, in Firefox to go Tools -> Options -> Advanced -> Network -> Settings and enter the IP address or host of the Squid proxy (e.g. 192.168.0.100) and 3128 for the port. Try to load any web page. If you see an access denied error, check out the http_access configuration in the squid configuration file.
Once Squid is all set and ready to go, you need to forward your connection to it over SSH. To set the tunnel up on your Windows laptop, download Plink, a command-line version of Putty SSH client, and run this command:
plink.exe -batch -N -l UserName -pw Password -L 3128:localhost:3128 SSH_Server
On Unix-based systems, simply run this command:
ssh -L 3128:localhost:3128 SSH_Server -f -N
Finally, tell your browser to use the SSH tunnel as a proxy. Basically you need to change the host to localhost and the port number to 3128 (See below).