1) If you want to make a public map, post it onto Mediafire and then onto the FH forum somewhere. If you want to upload to Mediafire, make an account. Its pretty straight forward from there. Once you've uploaded, post a thread somewhere on the FH forum(I really don't know where since I make private maps but I'm sure someone else will come along and tell you) giving the link to the download and maybe a couple screenies posted here and there.
2) If you have mutiple files to mess around with, then I suggest downloading either WinZIP or WinRAR. I don't know if either are free or not but just google one of those and you'll be on your way. If you don't have mutiple files, then you don't have to worry about putting it in a zip file.
Hope this helped? ^^