I am a Linux newbie.

I have an old HP iPAQ hx4700 which I mostly use as a calendar and note keeper.
It's fairly old technology now - 64Mb RAM, 128Mb ROM, 85Mb card and Intel (R) PXA270 processor. It is fairly battery-hungry, but it has a nice clear screen and it does the job I ask of it.

I also copy documents, maps, driving directions, booking confirmation pages etc. off websites via the cable connection, but I rarely bother with Bluetooth, Terminal Services or MSN functionality etc.

At the moment I synchronise it with MS Outlook on a work PC but fairly soon that will change and I may want to synchronise it with a home PC currently running Linux Ubuntu.

I found some old stuff about open-source for iPAQ but I suspect things have moved on a bit since then.

Basically I would want the following functions:
Web-based calendar/task list (such as Google Calendar or Remember the Milk?) which can be synchronised with an app on my PDA
Notes
Contacts
Task reminders
Spreasheet
Calculator
viewers for pdfs, WP documents, html pages, jpegs etc.

Can anyone offer any advice or recommend any websites etc. to get me started?