Offline files cache is stored in windowscsc folder on system drive. If the system drive is labeled c: then offline files cache would be stored in c:windowscsc.
As in windows XP, this location can be changed by editing registry database. Registry key for this is HKLMSystemCurrentControlSetServicesCSCParameters
Regkey : CacheLocation
Type: REG_SZ
By default cache is stored in [systemdrive]:windowscsc. If you want to move it to some other location you can do it by setting the above registry value to the path of the new location. Note that this path should be specified in NT format. For example, if you want d:newcachefolder to be the place for csc cache then you should assign the value ??d:newcachefolder to the above registry value.
Though we have this option of changing the offline files location in Windows XP too, the registry key path is different.