World: r3wp

Nicolas, try this:
do http://www.rebol.cz/~cyphre/scripts/r2/toys/imap-cli.r


this is very simple CLI for access to google IMAP server (others 
should work too).


Once you run it you can just type at thh prompt IMAP commands. Snippet 
of example session:

Script: "IMAP CLI in REBOL" (none)
{* OK Gimap ready for requests from 90.183.64.72 27if531665fxm.20
}
IMAP>>login user pass

{* CAPABILITY IMAP4rev1 UNSELECT LITERAL+ IDLE NAMESPACE QUOTA ID 
XLIST CHILDREN X-GM-EXT-1 UIDPLUS COMPRESS=DEFLATE
A0001 OK [user-:-gmail-:-com] authenticated (Success)
}
IMAP>>examine inbox
{* FLAGS (\Answered \Flagged \Draft \Deleted \Seen)
* OK [PERMANENTFLAGS ()]
* OK [UIDVALIDITY 2]
* 5989 EXISTS
* 0 RECENT
* OK [UIDNEXT 70472]
A0002 OK [READ-ONLY] inbox selected. (Success)
}
IMAP>>

Hope this can be useful...

I posted scripts on rebol.wik.is for working smtp and pop for gmail

These both work well with Gmail (extensively tested):

http://www.rebol.it/power-mezz/schemes/imapcommands.html
http://www.rebol.it/power-mezz/mezz/imap.html

Unfortunately the documentation is not very good, but it shouldn't 
be too hard to figure out where it differs from the actual code. 
Also, if you grab the repository from Sourceforge, there are a couple 
bug fixes to mezz/imap.r