Trying to play Blood 2, and I've got a slight problem. Any weapons I use shake, as though Caleb has Parkinsons disease. Any ideas?

try using the console "`" key. [Tilde key]
then use the command "maxfps 30" [without quotes]
Sometimes this helps.

Tilde doesn't work. I've tried entering it via say ("T"), but that didn't change anything. Also tried several different resolutions, widescreen and otherwise, but still no joy. It's really distracting!

hmmm, If I remember right there is a way to set maxfps in the Advanced Options menu before you start the game. I will investigate.
You might also try here: http://www.the-chosen.com/faq/blood2.htm#prob22
look under "flickering menu" and try that.
If you can get to your advanced menu settings, try to set them like this:

Tried both of those, but no good. It mainly happens when I'm standing still, and it only affects the weapons, and no other part of the screen. Bloody frustrating! Thanks for trying though. :)
I just recorded a gameplay video using FRAPS, and noticed that when recording the framerate dropped from 74 to 40, which stopped the shaking. So I need to change the framerate.

What is your monitor refresh rate? If its 60, you can try forcing vsync through your drivers (Nvidia control panel, or CCC)

Try adding the line
"MaxFps" "40"
to the autoexec.cfg and defaults.cfg files in the Blood 2 folder.

No joy on either of those. :(

If your on vista or win7 make sure to open notepad as administrator first then find the .cfg file and change the settings. You can run as admin just by right clicking on notepad and choosing run as administrator.

Yeah, did that, the Autoexec and Default saved fine, with the lines there, but it never solved the weapon shaking

You might also try FPS Limiter.

Editing the autoexec.cfg to have "MaxFps" "30" in addition changing the additional options to the following should fix it:
[X ] Disable DirectX 6 commands
[X] Enable optimized surfaces
[X] Enable poly gap fixing (slower)
[X] Enable triple buffering
You could choose "Always specify these command-line parameters" to help the game to force these options, even if you leave that particular field empty.

I'm having the exact same problem, havnt found a fix for it either. Running Windows 7 Pro 64-bit.

It's possible to also add it to the command-line in the advanced options, or you can make the configuration file read-only, or you can try entering the MaxFps command to the console that should open with tilde.