If you are thinking of CS4, you might want to check out CS5, which has just been announced this month. I don't really know how to compare CS3 and CS4, as I'm just starting to mess with it myself.

Currently, I'm using CS4. Look around for the Adobe Master Suite CS4 kit if you're not afraid to torrent things. CS5 is yes, the latest thing, but I'm not so sure how much of it is available via torrents.

As far as I know, you can. But I rarely mess with the brushes. I'll ask around. Or actually, you should ask  egypturnash

Creating a new calligraphic brush or double clicking a calligraphic brush in the Brushes panel menu brings up the "calligraphic brush options" dialog window. In the diameter section there's a drop down menu where you can change it from fixed to pressure.

I'm not sure if that's what you're exactly looking for, but if you need any further help just ask since I use Illustrator CS3 often for things. :x

no, I need to adjust the pressure curve AFTER the stroke's been created :C

Oh. D:

Hmmm, well the only option you got for adjusting a strokes pressure after its been created is selecting that stroke and going into calligraphic brush options, then messing with the variations in the diameter area. There's not many options for adjusting the brush sadly in CS3 (That I know of at least). There's also the paintbrush tool preferences for adjusting Tolerance and smoothness, but that's not what you're looking for I reckon.

I've gotten by with the lack of customization in the brushes though, and a lot of the lineart in the drawings you see in my gallery were done using illustrator. Sorry i couldn't be of much help, but I'm still available if you need it. Hope you figure out what you're looking for. :(

that's okay, no problem. I am wondering if this has improved in CS4 or 5...