To enable iCal iSyncing with the Sony Ericsson P800 and Nokia 3650, back up then open the file - /Library -> Application Support -> SyncService -> 501 -> SymbianConduitDefaults.plist. Edit the line that says:
<key>kNSSyncDeviceUseCalendars</key> <false/>to be:
<key>kNSSyncDeviceUseCalendars</key> <true/>[robg adds: I have not tested this...]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030607222924532