The only issue I ran into was this one (initscripts update) which requires simple manual deletion of a file for the update to succeed. This is currently the second news item on the Arch Linux front page, so it pays to check and be prepared.
After all that was done I decided it was time to bite the bullet and finally move the kernel up. I checked /boot and Grub entries and found that the install routine had made symlinks to vmlinuz26, so no need even to change my manual entries on the master boot record. And that was it !!!
Linux blackbox-2 3.1.1-1-ARCH #1 SMP PREEMPT Fri Nov 11 22:28:29 CET 2011 x86_64 AMD Phenom(tm) II N830 Triple-Core Processor AuthenticAMD GNU/Linux
Even found that the broadcom-wl package is not needed any more as this is now handled by the built in brcmsmac for the 43225 chip set. After blacklisting b43, ssb and bcma in modprobe.conf it was only a small matter of changing the interface in Wicd from eth0 to wlan0 for all networks to show up again. I'm used to interfaces requiring re-naming from working with various installations so it was the first thing on my mind when nothing showed up after the reboot. So far it seems at least as reliable as compiling the broadcom-wl module, possibly better.
Thanks to the Arch Linux team for the super smooth upgrade path after going four months without, and including a major change in version number. Even upgrading Debian is usually more problematic. A toast the modularity of linux, where you can update your userland but not your kernel or vice versa, or just some of it, as you please.
Celebrating by employing a new wallpaper from a recent ArchBang release. No need to reinstall here.