Upgrade kernel from backports in Debian Stable

Debian Stable (currently Lenny) is, as the version name implies, stable. If there are any annoying bugs, I haven't come across any, and I haven't experienced any crashes or lock-ups in the OS itself. Some of the packages in Stable are, however, rather long in the tooth- they haven't been updated for a couple of years or more.
Recently I've been using Debian backports to update versions of some applications- Pidgin, Transmission, Open Office. I'd come across a few recommendations to upgrade the kernel, but had trouble finding a simple guide to doing so. There are hundreds of kernel entries in the list of software packages in Debian Lenny: which one to choose? The best guide I found was this one.

For an example one package I recommend updating on a desktop system is the Linux kernel. Debian ships Linux kernels that are geared towards server use by default. This is fine if you are running Debian on a server, and if you are, I strongly suggest you stick with the default kernel. However, there are other kernels available that are optimised for desktop use...

The guide goes on to recommend a couple of kernel packages that are not in the current list of packages- so I guess they've been updated. I went ahead and installed linux-image-2.6.32-bpo.5-686, Linux 2.6.32 for modern PCs.
This seems to be the kernel for duel-core processors. There are many different kernels for different computer architectures. I'm guessing "bpo.5" stands for backport (something) 5- but if any reader knows better, or of a guide to choosing the best kernel for a particular computer, please leave a comment.
UPDATE: A comment informs "bpo.5" stands for backport.org.