What sort of financial incentives are available?

This is always a good place to start. The Federal Government offers a tax credit for residential solar systems installed after January 1st, 2009. The credit is for 30% of the installed cost of the system, which can mean that you will probably get thousands of dollars back when tax season rolls around. Note that this is a credit - not just a writeoff - so any credits received from the government go straight in your pocket!

Second, some states offer subsidies for solar systems. These usually come in the form of x dollars per watt. For example, the state of Colorado offers a $2.00 per watt rebate. These subsidies are usually in addition to the Federal tax credit. The best way to understand the subsidies in your area is to call one or more solar installers in your area and ask them about what options are available to you. Most installers are well aware of any and all credits available. If they are not aware of your options, that just might be your sign to keep shopping for installers.

What makes a good candidate for a solar house?

When looking at houses, you want to examine the property for its suitability for a solar array. The critical issues here are: roof orientation, roof age, shading, and home owners association rules. (Although your HOA may object, some states prohibit HOA's from prohibiting energy efficient features from being installed in or on a home.

Roof orientation is critical if you can't put the array in the yard. The ideal situation is a large south facing area. Northern and Eastern orientations are poor candidates for solar array locations. If the roof gets shadows on it during peak hours 9 am – 3 pm, you need to determine if those shadows can be eliminated. If they can't, the location is not suitable. Shading on panels will severely impact their performance. Even a small amount of shading can cut a panel's output by 80% or more! Also consider the condition of the roof. If the roof is nearing the end of its life then you will want to re-roof before installing the array. The installation itself is a very substantial portion of the cost of a system and if you have to disassemble the array to re-roof your house you will be incurring a large, and easily avoidable, expense. If you can have the sellers do the re-roofing before you even move, then in all the better. Finally, make sure that there are no HOA rules that would prohibit the installation of a solar array or that would prevent you from installing the array in the optimal place on the roof. If you are forced to install the array on an east or north facing roof face then you should strongly consider looking at another property or abandoning the idea of installing the solar array.