[gordon]

... but the clutch doesn't release.

Standard solution is to block the pedal completely down, put the transfer case in neutral (assuming it has a real one and not just one of those that disconnects the front axle) and then run the engine to warm it up.

When it's warm, stick the transfer case in low range, and with the pedal still blocked down start it in first and just crunch round slowly till the clutch decides to break free, using the ignition switch and brakes together in case of scary moments.

Remember to block the pedal down again after it's freed off to prevent it happening again.

Gordon