http://discussions.mea.nokia.com/t5/Eseries-and-Communicators/E52-Hard-Reset-Does-any-key-combination-really-work/m-p/571682
Really useful post on how to reset / reformat Nokia phones. *#7780# - Restore factory settings and *#7370# - Reformat. Handy dandy.
http://www.mobile-webster.com/Series60.html
A bunch of dictionaries for Symbian devices, including Spanish to English. :-)
http://developer.symbian.org/wiki/index.php/Podcatcher_package
The podcatcher application for Symbian, the successor of Escarpod.
http://www.mobuzz.co.uk/2009/08/19/nokia-e52-and-e55-internet-radio/
How to install Nokia's internet radio application on the E52, E55 and E72. Reports that it works.
http://symbianoggplay.sourceforge.net/
Open source media player (supports mp3, ogg, and more) for Symbian devices. Great for the E51, much better than the in-built player. Supports skip forward / back... :-)
http://s2putty.sourceforge.net/
SSH client for Symbian OS for phones like the Nokia E51 and E52.
http://www.navicoretech.com/Consumer/Support/Downloads/tablet/en_GB/wfnavigator/
Download maps for the Map application on the N810 tablet without using the in-built software. Very useful. :-)
http://mediautils.garage.maemo.org/tablet-encode.html
A bloody handy little perl script called tablet-encode which automatically transcodes video files into a good format for the Nokia tablets. Even has a GUI (which doesn't work for me) through gtk2-perl. :)
http://www.claws-mail.org/maemo/
Claws Mail is a lightweight mail client. The maemo port is specifically for Nokia tablets and supports advanced features way beyond the default mail client, such as imap folders, etc.