Iraq alone has over 10,000 of these foreign security personnel on duty. Worldwide demand is about triple that. In the next year, over a hundred million dollars will be spent, in Iraq alone, on these commercial security forces. The problem is, the recruiters are going after the most experienced troops available, no matter what country they are serving in. If you can speak English (which is the common language of international business) and have at least five years military experience in the appropriate area (military police, special operations and so on), you are recruitable. The standard offer is two to three times what you made as a full time soldier, plus fringe benefits. Even experienced police are being recruited, especially if they have SWAT experience. Smaller nations, like Chile, are finding their ranks being depleted as recruiters lure away some of the best trained and most experienced officers and troops. It's hard to pass laws to stop this "poaching," as that smacks of slavery.
Because there is a limited pool of highly trained, English speaking soldiers and para-militaries (SWAT), the demand for quality security professionals is making a dent in the existing armies and police forces. While many of those recruited are recently retired, the recruiters have found many men (and some women) willing to quit their current service and go commercial. There is also fear that this large pool of experienced security troops could provide a large enough group that unscrupulous operators could put together traditional mercenary units for less legal enterprises (like propping up dictatorships or overthrowing legitimate governments in small countries.). When the war on terror eventually dies down, in a decade or so, there will be a lot of "commercial soldiers" cut loose. Some of them will be tempted to work for less savory employers. This could be interesting, and, at times, quite nasty.
The continued disorder in Iraq and Afghanistan, and general increase in violence by Islamic radicals, is causing an enormous spurt in demand for professional security personnel willing to work overseas. Companies are increasing security at their foreign operations, and providing more bodyguards for their key personnel. While you can always hire security personnel locally, the Islamic radicals are proving capable of infiltrating local security forces. So large organizations are paying more to bring in skilled foreigners to take care of security.