Whilst thinking further about the Nokia E61 and Sony Ericsson M600 I was wondering whether their email functionality would actually be any use for those of us who don't pay to use a proprietary push email system or run a costly solution like Microsoft Exchange, i.e. normal Joes who just use standard mail servers with POP3 or IMAP access.

There's a simple solution: IMAP IDLE. Rui has a great collection of IMAP resources, including RFC:2177 the IMAP IDLE command.

Here's a sample IMAP IDLE session using telnet, the commands I typed are in bold, with a few of my comments in italics, all the rest is traffic back from the server.

jim@server:~$ telnet example.com 143
Trying 192.168.1.68...
Connected to example.com.
Escape character is '^]'.
* OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS] Courier-IMAP ready. Copyright 1998-2005 Double Precision, Inc. See COPYING for distribution information.
we'e connected to the server, spot the word IDLE in the capabilities?
? LOGIN jim password
? OK LOGIN Ok.
? SELECT INBOX
* FLAGS (\Draft \Answered \Flagged \Deleted \Seen \Recent)
* OK [PERMANENTFLAGS (\* \Draft \Answered \Flagged \Deleted \Seen)] Limited
* 606 EXISTS
* 0 RECENT
* OK [UIDVALIDITY 1152176239] Ok
* OK [MYRIGHTS "acdilrsw"] ACL
? OK [READ-WRITE] Ok
? IDLE
+ entering idle mode
time passes ... and a new email arrives!
* 607 EXISTS
* 1 RECENT
at this point we could use the FETCH command to grab the new message, but for simplicity we'll just bale out
DONE
? OK IDLE completed
? LOGOUT
* BYE Courier-IMAP server shutting down
? OK LOGOUT completed
Connection closed by foreign host.
jim@server:~$

As you can see, the basics of getting the IDLE command working for a client are pretty straightforward, and the best bit is that native email client on a number of phones such as the Sony Ericsson P910 and the Nokia 6680 already appears to support IMAP IDLE. So who needs a Blackberry? :-)

Updates: A quick thanks to Rui who confirms that most recent Symbian and Sony Ericsson phones (such as the K610i) should have IMAP IDLE support, and also to Martin for investigations that prove our hosting provider JaguarPC supports IMAP IDLE - all for a mere 8 bucks a month.