I am not an expert on this subject at all (and there are people here who are, so listen to them more than me) - but I will throw my thoughts into this mix:
First off - what are you doing this for? Is it to save money, energy, both? Mostly likely it is - so have you already done everything else possible to your house in preparation for this? Things like extra insulation, better windows (double or even triple pane), efficient heating/cooling systems, attic ventilation (where necessary), planting of shade trees or other passing shading measures. Have you changed out your lighting system for things like CFLs and/or LEDs (where possible and/or desireable)? What about weatherstripping and caulking for leaks? There are many more things you can also do/look into - all of these measures (and more - one of the hardest ones to change is your daily energy usage habits, but its also one of the ones that will save you the most!) will save you money, and should be put into place/practice long before you get a solar panel system put into place.
Once you have done so, then I say as a beginner, seek professional help: Look for and hire a contractor who has experience (or better, specializes) in residential solar installation. This will have many advantages, not the least of which is you will get a system which will work and not burn your house down or cause other problems for you as a homeowner (like being up to code, etc). He'll also be able to determine (or hire a civil engineer to determine) if your roof or wherever you plan to place the panels can support the load/weight.
You also want to think about whether you want a grid-tie system or not; grid-tie ties the system into the grid - you run off the panels mostly, but the grid acts as your "battery backup" (mainly at night or on cloudy days). In this case, you still pay money to the electric utility company, but less than you would without the solar panels. Non grid-tie systems use a battery bank (which is something you would need to maintain and service, not to mention have a place for storage of the bank). Both systems use inverters to convert the DC voltage from the panels to AC for the house. You might also want to think about a solar water heating system to go along with the electric providing panels (depending of course on how your water is currently heated - alternatively, you might look into tankless heating solutions as well).
Another thing to think about is your roof: When did you last have it replaced? If its been a while, or you don't know they age of the roof, or you can't remember - then consider getting it replaced -before- you install the solar panels, mainly because if you find you have to have the roof replaced later, you'll have to hire a contractor or other service to remove the panels prior to the roofing being done, and having them re-installed after the roofing is completed - which will only add to the cost and inconvenience (and if the installation isn't a grid-tie system, that inconvenience might be large). When you get your new roof, go for one that won't need replacing for 30-50 years, depending on your age (make the roof-replacement issue something for the next homeowner to worry about).