If you're rooted you can do this through the terminal. I believe you have to mount the filesystem first, as follows:
mount -o remount,rw -t yaffs2 /dev/block/mtdblock4 /system
IIRC, then you can delete the apps. Deleting is a bad idea though, in case you ever need to restore them. The best thing to do is rename them by changing the extension. Using .bak is a common practice. You would navigate to the system folder after mounting and do something like this:
mv CorpCal.apk CorpCal.bak
That would change the Corporate Calendar app so it is no longer a valid application. If you ever need to restore it, you can just "mv" backwards so it's an APK again.
If I made a mistake here, please correct me. It's been a while since I used
linux and I'm not an expert on Android terminal commands.