The ignition switches now dont carry any significant current, it is possible that a relay that is switched by the ignition switch has stuck on.
using ur owners manual locate the fuse/relay board and tap each relay and see if things that are on that shouldnt be go off.
Look up what is on in the user manaul and fnd what relay controls that circuit.
Car power supply is in 3-4 circuits.
1) 24h power - this goes to alarm, clock, ignition switch, interior light etc
2) low power - things like radio that are on position 1 of the key switch
3) high power - fans, blower, engine management, preheaters etc, normally position 2 on key
4) start-up - starter etc comes on when you turn the key to the temporay start position, Air con and pwr streering is also switched off on some cars at this point so the starter isnt turning thoes devices.
If you find that with no key, the blower is running but the radio isnt, then you know the relay that isolates high power circuits is stuck.
If only radio and other low power things is on then its the low power relay.
Locate and remove the appropriate relay from the fuse/relay board and see if the things go off.
If they do then its a �10 relay.
Such basic fault finding can be done with some time and thought and save much money. When doing these things always have 2 people, never work alone for saftey - also 2 minds are better than one :)
Stuart.