In the Control Panel for the pen, hold down CTRL (PC) or ALT (Mac) and click on the About button to open the diagnostic screen. Look at the value for "Pressure" on the right hand side - this should stay at 0 until the pen is brought into contact with the tablet.
If it shows a high value (above 50), then you pen may be defective and, if in warranty, will be replaced. A half hour ago, my pen gave a value of 220 and, being well out of warranty, cannot be replaced for free. However, it now gives a value of 0 and works perfectly. The solution? I bashed it (side on) on the table top and against the flat of my hand for about 10 minutes as per a low-tech solution on the Wacom-Europe forum. With each series of smacks, the pressure fell toward 0. If you can't get it below about 60, it may still be okay as there is a pressure offset control in the diagnostic panel that goes up to 59.
Good luck! Alastair.

***actual solution***
Hinted by the solution by leahyudle I investigated the problem further.
My stylus was also stuck at 230 min. pressure.
So I disassembled the stylus. This is a quite brutal prcedure. the upper part is actually slid over the lower part, so to seperate them hold the rubbery part tight and bend the silver upper part arround till it moves (it may crack a bit before that, but thats just a cosmetic problem. After you pull the stylus apart, pull the PCB out and notice the coils on both ends. Pull the tips out of the coils and then the coils out of their holders (the wire should be long enough). Then you have to seperate the gray part of the sensors from the black part using a small screwdriver or something similar. whenn you then bring one of the coils near the pad, the pressure should read zero.
Carefully clean the sensor parts and put them back together, check pressure again. It should still read zero. If not, clean again.
The problem is most probably that a bit of dust or a grain of sand squeezes itself between the tip and the very sensible sensor and therefore preloads it.

I know this is an old posting, but I'm sure others (like me) are still having this problem where the Wacom pen just won't quit. Mine was taking anywhere from 2-20 seconds to release from the last activity. I had to remember to hold the pen very still over the last point of contact until the Photoshop history registered the last activity. If I was selecting an area, and moved the pen, the selection area would have all sorts of weird angles added to the desired area. If drawing with the brush tool, I would get streaks wherever the pen was hovering over the tablet. Frustrating, time-consuming, aggravating. I tried all the above suggestions 4 months ago. Finally replaced the nib (can't believe I actually found the original package from a few years ago), and it worked for a while, then started acting crazy again. I am in the middle of big drawing projects, and was ready to scream the other night, as every action took ten times longer than it should have as I waited for the pen to release. I finally pulled the nib out with needlenose pliers, rubbed it, replaced it. No change. Pulled it out again and, this time, blew into the nib hole in the pen a couple of times before replacing it. I hesitate writing this, dare I jinx it, but the pen has been working perfectly ever since. Maybe there was some dust on the contacts? Anyway, it was an easy and inexpensive fix. Not sure it will always be the fix for every situation, but it's worth a try. leah