Most guitars (especially Fenders) are very simple to dismantle. This is something I posted in a thread a little while ago. My tremendous ego decided it needed to be blogged and preserved.
1. To begin, you'll have to remove the strings. To do this you simply have to unwind them from their tuning pegs and thread them back through the bridge and body. You may want to remove the back plate before this to make it easier.
2. On Squiers, and most Fender Stratocasters, the neck plate is held on by four screws:
Carefully unscrew these, being careful not to cross-thread them. If you are only changing the neck, align the new neck with the screw holes, re-screw, replace the strings and carry on with your day.
1. If you are changing the body, you will need to remove the pickguard (with electronics), jack plate, bridge, and strap pins. Begin with the bridge. If you have not already, remove the plastic back-plate. Underneath will likely be three to five springs attached at one end to the underside of the bridge, and at the other to a claw anchored in the body:
Begin by loosening the screws holding the claw to the body. Eventually the claw will detach and you can remove the springs (put them in a safe place, they are important.) Do not remove the claw yet, it is still attached to the ground wire.
Flip the guitar over and remove the six screws at the front of the bridge (top in this picture):
You can now remove the entire bridge. If the saddles have come off, you've undone the wrong six screws. Try again.
2. Now it's time to remove the pickguard. Most of a Stratocaster's electronics are entirely attached to the pickguard, so it's very easy to remove. However, you will need to de-solder 3 wires. We'll get to that later. To begin, remove the 11 screws attaching the pickguard to the body. Do not remove the screws holding the pickups to the pickguard, they don't need to be undone (be careful because the top screw on the neck pickup looks like a regular screw. It isn't, it's an impostor.) You can now lift up the pickguard, but there will be 3 wires holding it to the body. Two of these are grounding wires, they are almost always black, and are soldered to the back of the volume knob. The two wires you need to un-solder are the one from the claw at the back of the guitar, and the one which comes from the hole leading to the jack (this one will be accompanied by a white wire) Un-solder these, without un-soldering the grounding wires for the pickups if possible (they can be re-attached later if necessary).
The last wire is a (probably) white wire coming from the jack. This is a hot wire and should be soldered to the middle lug of the volume pot. Dispatch it like you did the others, and the pickguard can now be lifted clear of the body.
3. The last two things left to do are to remove the jack plate and the strap pins. These are simply held on with screws. Undo these and you are finished.
To replace all the parts into another body, simply do them in reverse order (be careful not to solder wires until they're in place, ie, don't solder the jack wires until the jack is in place)