Hi.

- The Case -
I am building a linux server [on a PII450MHz CPU/64MB(possibly more) RAM/4GB HD] for a friend's office and I'm looking for some software (open source) for the following applications:

1. Groupware
........support for shared Calendar, To-Do, Address Book
........it must provide support for GUI clients (preferably) for linux and windows and/or webUI. The windows client doesn't has to be open source (eg. Lotus Notes support would be great)

2. Database
........I have a database file in MS Access that I'll have to covert, so a db server with conversion tools would be great (I think postgresql has one)
........the db to be used is simple, I believe, with less than 20 fields per sheet and it's something like an address book with some extra fields such as "Serial Number". The only fields that will need to be searched is "Name"
........it must support GUI clients preferably and/or webUI. The users aren't much of a power-user so an easy UI would be very nice
........all users will need write access
........there won't be more than 5 or 6 users at max connected to the db

- The Facts -
I'm relatively new to linux (I've been using it as my standard OS for a year) and completely new to db's and groupware software, so some info for easy configuration tools would be great.
Also my preferred distribution is Debian but I could cope with another if it's trivial for the suggested software.
Stability is needed.

Thanks in advance.

For Groupware, eGroupWare http://sourceforge.net/projects/egroupware/ is the choice.
For Database, both MySQL and PostgreSQL work, but I prefer MySQL, since it's simpler than PostgreSQL, and the 4.1 version is more stable and performable than before.

you may also want to check out open-xchange. I've used eGroupware in the past as well...seems to be an OK product, but I was finding bugs (which could have been a cause/result of the fork of the project from PHPGroupWare.

If I remember correctly, the Horde Project was also talking about collaborative calendaring some time ago, and I generally like the IMP mail client

http://www.open-xchange.org
http://www.horde.org