First off. Do your research. Lots of research. Properties in Florida require different maintenance then properties in Canada. (power washing for moss/mould, insect control) because of the humidity. That being said.... get yourself a Realtor there that you trust. Particularly south of the border. Their real estate laws are different then here. A larger portion than normal of Realtors in the States, at the moment, are 'hungry' so be careful and ask lots of questions.
A Realtor familiar with living in Florida will be able to answer your questions about maintenance, financing, foreign ownership etc. It wouldn't hurt to talk to an Accountant here and south of the border and a lawyer to answer your questions about being a foreign owner of property in Florida.
When it comes time to purchase and put an offer in, insist on a condition in the sales offer of home inspection. It was mentioned that many properties were constructed shoddily in the 90's up. Although a home inspector won't open walls they will have a better trained eye to look for signs of structural deficiency, water damage etc. Note that most of Florida is swamp land and at sea level. As a result, a good portion of the homes are built on concrete pads with no basement. Keep an eye on the floors for signs of shifting and water seepage from ground water coming in. (I'm not an expert but common sense dictates). Also MOULD. Make sure the house inspector looks for signs of mould. (A little isn't going to kill you (make sure it's taken care of should decide to purchase) but if it's running rampant in the home run away). Flip side is that it's a sub tropical to tropical area so the high humidity makes mould a more common thing and hard to avoid. Use your common sense and ask lots of questions and get a second opinion if you are not satisfied with the first one.
From a financial perspective also insist on a condition of clear title or something along those lines (This is where talking to a reputable real estate lawyer before hand comes in). There have been a lot of foreclosures in the U.S. You want to make sure you are protected should future problems with title or financial liens arise or ideally that no problems with such will occur.
All in all there are some very good real estate deals to be had in the US at the moment but remember that an ounce of prevention is a pound of cure. Talk to professionals who know the details.
Hope this helps. I'm not an expert on Florida real estate or foreign property ownership but hope I've helped to guide you in the right direction to make an informed purchase.
Cheers
Tim