My dell axim x30 backup battery needs replacing. Is this something I can do myself?

I believe if you are a bit of a hands on type of person you should be able to do this yourself.
but not without researching !

read this page, should tell you everything you need to know, from the perspective of someone who had to do the same changing of the CMOS battery.

http://www.mobilitysite.com/boards/x3-x3i-hardware-troubles/96005-x3-backup-battery-revealed.html

or read below:

quoted from: Tenc hi4U

DISCLAIMER : I take no responsibility for any damage you may cause to your Axim. The parts and proecedures described in this guide refelct my own experience with my own Backup Battery (BuB) in my girlfriend's Axim X3. Your mileage, parts, anbd experience may vary.

Tools needed for successful BuB replacement:
1. fine tip jeweler's screwdrivers (helpful if you slightly magnetize the tip)
2. Varta V20HR rechargeable NiMH battery
3. electrically conductive silver epoxy
4. strong needlenose pliers
5. electrical tape or heatshrink (razor blade or scissors to cut to shape)

But here it is step-by-step:

1. Pop little rubber caps from 4 corners of back covers. Disassemble Axim X3 with small jeweler's phillips head screqwdriver. Be sure to plave all parts in a plastic bag or other container (4 scres rear cover, 2 screws near port). Disconnect the ribbon connector towards the bottom of the PCB and the speaker wire (also on the lower portion of the PCB). Backup battery should be the green covered circular item under the pcb).

2. Locate backup battery, Cut away BuB cover, & CAREFULLY use strong needlenose pliers to grip and "roll" the leads off of BuB.Be very careful with the leads.

3. Mix dime sized batch of silver conductive epoxy (do NOT hot solder this battery, heat will lead to BuB damage and destroy lead connection to wire).

4. Apply epoxy to both sides (not too much)and afix respective leads to respective side (red lead goes to +, black lead goes to -). Secure connections with some type of clamp (I used a binder style paper clip, but a wooden close pin or something else that will hold the leads to the BuB while the epoxy cures (Mine took 24 hours to cure).

5. Recover new BuB with protective covering (I use electrical tape cut to the shape of the BuB. Covering WILL have to be form fitting to fit back into Axim BuB "slot".

6. Reassemble and charge Axim and charge.