I used the upgrade advisor to check for issues running Windows 7 on the laptop, and didn't see anything nasty.
I then used the Windows Easy Transfer program to backup my profile and shared items, putting them on a USB drive.
The installation process was seamless, and I just had to leave it chugging away for ages until it finally got to the regional settings and product key screens.
However, on the first 'clean' boot (after installation was complete), I discovered that I had no network or sound. My network adaptor is an Intel 2200BG, and I thought that there was a windows 7 driver on Intel's website. Instead they categorically stated that this adaptor was not supported on Windows 7. Other windows forums had posts about the XP driver being suitable, so I gave it a go - and it worked perfectly, and then all other missing drivers were installed. Note that I had another PC hanging around to search for and download the network driver from Intel.com before swapping it to my USB drive. A spare computer can be really handy during an OS upgrade!
One thing I need to read up on is the Microsoft HomeGroup, which presumably allows more secure sharing between computers - without using actual user account logins, maybe?