after reading a bunch of stuff here and there.... i finally dove in head first.
Took me about 4 hours to figure it all out.... I didn't realize there there are 2 instances of mysql running, one for plesk itself and the other one is for the client databases.....
basically it turned out to be quite simple to do...
I shutdown both mysql servers....
I then downloaded just the files from mysql.com
I extracted the zip file and deleted the data directory on the new install files...
i then copied over all the files in both mysql directories....
I then tried to start mysql but it gave me a system error 1067
so i deleted the log files in data and then tried starting again and it worked.
Then i started the plesk instance using the system monitor.
I logged into plesk and it said it was still running 4.1.18 mysql.. but i installed 5.0.67
I then had to go into add/remove programs and then i re-installed mysql there with version 5 and now it shows the correct version in plesk