possible solution (got the CSC changed on mine with it, market is still an issue though, need to solve that one still, maybe one of you can figure it out and let me know)
1. you need your phone rooted (superoneclick 1.7 works)
2. get Titanium Backup and back up all your files
3. save your contacts or use titanium backup to back them up
4. get root explorer
5. follow these steps:
http://www.emoiz.com/how-to-change-restore-your-csc-on-samsung-galaxy-s-i9000
Remarks: the link allows you to add CSC's to your phone, installs them and with it hard resets your phone
EDIT: i GUESS the problem i face with still not being able to access market is that even though the CSC was changed, the PDA n PHONE files have not been adjusted to the new CSC and therefore market doesnt start...
check by dialing *#1234#
got now:
PDA: I9003ZCKA7
PHONE: I9003ZCKA7
CSC: I9000ZSJH1
do these have to be the same to make market usable? if so... where can i find fitting files and how to change them/add them to my phone?
or is it probably enough to just copy and paste the market app in the CSC app folder to have it preinstalled?
can any1 confirm that please?
EDIT: can't get market to run with this method, no matter what
suggesting to load/flash new firmware instead
speak: root the phone, back up your data, load new firmware, update firmware using Kies, root your phone again since new firmware means hard reset and restore backed up files