Super-simple HTTP downloading guide! To set up HTTP downloads from your R1Q2 server, you will need some webspace - doesn't matter where as long as it isn't on a free host that will start serving up "Bandwidth exceeded" pages instead of content...
Simply upload all files you want to offer via HTTP downloading to your webspace. Then set sv_downloadserver to the URL of the root directory of your webspace. Example:
You want to allow HTTP downloads of all your custom lmctf maps. You run a Q2 server where the gamedir is 'lmctf'. Your website is q2downloads.com. You woud login to your webspace, make a directory lmctf, make another directory inside that called maps, upload all the .bsp files to the maps directory, then set sv_downloadserver to http://q2downloads.com/
Easy enough, wasn't it?
. Remember, the trailing slash at the end of sv_downloadserver is very important!