It's a fairly easy process.
1) Make sure you've tested and fixed any glitches in the map before releasing. It'll make things a lot easier if you get that out of the way first.
2) Take an overview of your map and upload it to a site such as
Imageshack
3) Zip up your map, all sceneries used, textures, etc. in the appropriate folders. If you name the folders the same as the ones in your Soldat folder it will make it much easier for other people to download.
4) Upload this .zip folder to a site where other people can download it. I use the
M00net Uploader for the majority of my maps.
Hope this helps.