I bought a blow torch but I really hate using the stupid thing, it keeps going out when I tilt it from side to side and if it is cold forget it. What really works best is a heat gun!! It is consistent and has no open flame to hurt the paint and it doesn't go out. When you heat up the wheel hub it gets bigger around and expands away from the bearing ever so slightly. 

No they won't just fall out- but you should be able to now move the spacer tube to use a puller or alignment punch. I also smeared a bit of grease around the inner hub. One time the wheel had cooled off and I just couldn't get the thing to budge so I heated the hub back up again (not the bearing itself) and it came right out with only a few more bumps with the slide-hammer puller. 

When installing new bearings, heat the wheel hub with a heat gun moving it around. You'll know when it is hot enough and then have your new bearings in the freezer for at least a couple of hours first and with a little grease and the proper driver set they should slide right down evenly, just enough to seat into the lip flange. Make sure the spacer tube can still be moved and retainer clips should pop right in and out. I had lot's of people that worked at bike shops tell me not to attempt it myself, but I am so glad I didn't listen and waited to do it at home. Don't over torque.