How many foreign troops are stationed in America?

Yes, but not in the context which the Alex Jones types make it out to be. For example, NORAD is a joint US-Canadian operation, thus there are Canadian military personnel stationed at Schriever Air Force Base. Some countries use their military to provide security for their overseas embassies and consulates, so those troops are stationed within the US, although technically they're stationed on the soil of their home country, since embassies are considered part of the country which occupies them, rather than the country hosting them.