I too was experiencing the problems that many are describing where the charging icon would stay on for about 2 seconds and then disappear.
I am using Ubuntu 7.04 and a Blackberry 8700r with OS 4.2.
What appeared to be happening was that when bcharge ran, it did indeed set the power output to the appropriate level, but then something else seemed to drop it back down about 2 seconds later.
The work around I found...which is by no means a fix in the strictest sense...was to write a script that runs bcharge every 1 second.
Now I plug in the blackberry, run the script and blammo...a charging blackberry.
My detailed procedure if required is Here