Have you heard the term "shadow inventory" recently? Shadow inventory pertains to houses that are falling into a "no man's land" after banks foreclose on them.

Here's the scoop: The nation's banks have not been staffed adequately to deal with the vast number of foreclosures throughout the country. Even as the banks ramp up their REO (real-estate owned) departments, they're still falling behind. As a result, it's believed that more than half a million properties are falling by the wayside.

That's the shadow inventory.

According to a recent San Francisco Chronicle report, there are an estimated 600,000 foreclosed homes of this sort right now. The banks aren't getting them ready for sale and they're certainly not maintaining them in any way.

Neighborhoods suffer greatly from shadow inventory. Unused houses tend to attract vandals, squatters and a host of other troubles.

But as an investor, shadow inventory is a source of great opportunity. As these houses sit and go unmaintained, there will be many that have nothing fundamentally wrong with them; they just simply look and smell awful. That means no one else wants them and you can swoop in to steal a deal.

On another note, Clark believes that until the banks come to terms with their shadow inventory, we can not truly call a bottom in the real-estate markets around the country.

Meanwhile, a recent RealtyTrac study analyzed foreclosures in 4 states and found that 70% of them were not showing up in the MLS. Either they've gone into the shadow inventory or the banks put them up for sale as REO but without any agent representation in the MLS.

So how can you tap into shadow inventory as a first-time homebuyer or an investor? Go to the websites of individual banks and look for a link to their listings. You used to have to hunt around for this kind of info, but now you'll usually find it linked directly on their homepage.

This gives you the ability to potentially ferret out a bargain before others get it through an agent and the MLS.

Does that mean you don't use an agent? No. If you a hire a buyer's agent, you need to have a written agreement stating that they only represent you on properties they show you. You don't want a blanket agreement where you owe them commission on any property you buy -- even if they have nothing to do with locating it.