Has the car been de-locked? You should be able to open by turning the key in the doorlock.
If you have a set of jump leads and a spare battery you can connect the spare battery to the main terminal of the starter motor and the other end to a good earth. This will power up the system allowing you to unlock the doors. Make sure you get the positive and negative the right way round though!!!!
I accept no responsibility if you fry the cars electrics.
gerry
September 2011