A while back I posted about the HP Mini 1000 and some of the ways it can be upgraded. Probably the easiest upgrade is to the Transcend JetFlash T3 drive that comes with the machine, and fills the recessed USB slot. The Mini comes with a 2GB drive, and the easiest upgrade is to simply purchase a higher capacity Transcend drive in the same line. The 4GB unit is priced at $16.70 on the Transcend store website, or $16.29 from Amazon.
I found a neat alternative. Kingston offers a MicroSDHC card that comes with a MicroSDHC card reader whose form factor is very similar to that of the JetFlash T3. The 4GB card with reader is priced at $14.95 through Amazon currently. I wanted to upgrade the MicroSD card in my GPSr anyway, so this seemed like a good opportunity to try it out.
The first thing I noticed when I got the package was that the MicroSDHC reader is about 20% shorter than the Transcend card. Aside from that, the form factor was perfect. I slotted the 4GB MicroSDHC card into the reader, and then slide it into the small holder that covers the recessed USB port on the Mini. I slid everything into place, but nothing happened. Unfortunately, the shorter length means that the pads don't quite reach to make a connection to the USB port. All is not lost though. With a bit of fiddling, I found I could get the reader to slot into the recessed port without any issue. At that point, I can leave the cover on or off, it doesn't really matter, as the reader is completely within the recessed slot. If you do want to keep the cover on, be sure to slot the reader into the cover first, as trying to push the cover on over the reader after it has been slotted is a chore. Getting the reader back out again is a bit of a trick, but nothing you couldn't do with a handy set of tweezers, or a small set of needle nose pliers.
Given the lower price of MicroSDHC card and reader at the same capacity, I think this is a pretty good way to upgrade your machine. Another advantage is that, as MicroSDHC card capacities increase and prices drop you can continue to upgrade this part.