You do not have to use Enigmail to do that. In fact I am not sure how to do that with Enigmail.
Use gpg commands (command line)
Code:
gpg --keyserver pgp.mit.edu --send-keys YOURID
man gpg for more details:
Code:
--send-keys [names]
Same as --export but sends the keys to a keyserver. Option
--keyserver must be used to give the name of this keyserver.
Don't send your complete keyring to a keyserver - select only
those keys which are new or changed by you.
And also read the first chapter of the manual available on gnupg website.
Alternative to command line sending. You can summit your public key via web interface. Just do a search on pgp keyserver. And click any of them. The gnupg handbook on this:
http://www.gnupg.org/gph/en/manual.html#AEN65
on your machine
Code:
gpg --armor --export USERID >> USERID_publickey.txt
and submit the content of the file to the pgp keyserver.