string functions

hi there!
i've got some email adresses in my db, but i just want everything before
the '@' to be returned.
example:

firstname(dot)lastname(at)mydomain(dot)tld -> firstname.lastname

what must my select statement look like?

i tried something like
"SELECT TRIM(leading '@' from email) FROM ..." needless to say that this
doesn't work.

thanks in advance!

PS: looking at "user-7.2-A4.pdf" and "user-7.2-US.pdf" in
ftp://ftp.at.postgresql.org/db/www.postgresql.org/pub/doc/current/ i had
to find out that many examples cannot be read because of too narrow
columns. are there other versions of these docs available (html, rtf,
...)?

--michael