To dump / backup your IMAP Mail Folder to a local directory, there are some projects in the Ubuntu repositories:
looked for last changes on 2010-01-10
- imapcopy - pascal http://home.arcor.de/armin.diehl/imapcopy/imapcopy.html last change: 2006-04
- imapsync - perl http://www.linux-france.org/prj/imapsync/ last change: v1.286 2009-07
- offlineimap - python http://software.complete.org/software/projects/show/offlineimap last change in git repo: 2009-08
- syncmaildir - C and Lua/Shell http://syncmaildir.sourceforge.net/ last change: 2009-12
not yet in the repositories
more found on http://www.linux-france.org/prj/imapsync/README → SIMILAR SOFTWARES :
- imap_tools (in Perl) http://www.athensfbc.com/imap_tools
- UW IMAP toolkit: ftp://ftp.cac.washington.edu/imap/
- imaprepl - Perl http://www.bl0rg.net/software
- larch - ruby transfer IMAP to IMAP (including GMail) http://github.com/rgrove/larch evolved from a script on http://wonko.com/article/554
The solution I took was offlineimap as it looked pretty mature to me and as development on the project continues.
I describe my setup of offlineimap here.