Okay; open utorrent.
Under "File", select "Create New Torrent...."
In the dialogue, select "Add File".
Navigate to your file location and select it.
In the "trackers" pane, paste the folowing:
http://tracker.openbittorrent.com/announce
udp://tracker.openbittorrent.com:80/announce
Make sure piece size is on "auto detect" and "start seeding" is checked.
Click "create and save as", select a location and type a name for the torrent which can be anything, but Ideally it is not too long and it is NOT EXACTLY the same as the filename of the file you are sharing. If it is, the torrent will still work, but will be difficult for your D/L'ers to deal with. A good example in your case would be "FILENAME.ISO.by.BB.torrent"
That way, your D/L'ers can readily ID your file in their transfer list, the filename of the .torrent file is not TOO long, and there is a way to differentiate YOUR release from someone else's.
Once you have the torrent, I advise you to leave it seeding as much as possible for as long as possible. This is so the trackers have time to pick up your torrent and Google has time to index it.
Public trackers are falling out of favor lately, mainly because greedy a$$holes in the content creation/distribution industry are clamping down on file sharing sites with money, now that they couldn't do it with the law.
Once you have the torrent seeding, right-click the file in the transfer window and select "copy magnet URI".
Paste that as a link to any site or forum and it will be available to anyone just as my file was available to you.
And if you'd rather e-mail the .torrent file to someone, simply form it as an attachment to that e-mail.