I recently installed Ubuntu 9.10 on a Dell D610 and found that it was a pretty easy install provided that you have the right hardware installed in the D610. I have since installed Ubuntu on many D610 that I have sold in my business. The reason most customers give up the idea of Ubuntu on there older hardware is that Ubuntu does not recognize all the hardware in the laptop. They still want to try Ubuntu but do not think they can get the operating system working right. If your hardware does not work right with the Live CD most users are in for a lot of problems trying to get it to work. I still have a old computer in my shop that I could never get the sound card to work. It is a shame because I wanted to put it out by the pool and listen to music. This is where most of the frustration comes from when dealing with Ubuntu.
I have had no problems with the installation on the Dell D610 except for the wireless card in the D610. I found many questions and and articles on the internet about the wireless card not working in a Dell D610. Or not being able to recognize the card under Ubuntu. That is true if you have anything but the Intel wireless card installed in the D610. The Intel card works right out of the box and the Broadcom card is not recognized. My suggestion is check and see if you have a Intel card, and if not get one before you install Ubuntu 9.10. You can find one on eBay relatively cheaply if you search for the Dell D610 Wireless card. The part number for this part is K3444. Beware though that there is on odd thing that you may run into with the wireless. The light that indicates that the wireless card is working does not light up when in use. This does not harm or change the way the wireless card works it just does not light up. The card works perfectly so the lack of a indicator light is a small price to pay.
I have not run into any other problems installing Ubuntu 9.10 on a D610. Most of the time the process is very smooth.