For people reading this that use Angular 2 rc4 or later, it appears LocationStrategy has been moved from router to common. You'll have to import it from there.
Also note the curly brackets around the 'provide' line.
main.ts
// Imports for loading & configuring the in-memory web api
import { XHRBackend } from '@angular/http';
// The usual bootstrapping imports
import { bootstrap } from '@angular/platform-browser-dynamic';
import { HTTP_PROVIDERS } from '@angular/http';
import { AppComponent } from './app.component';
import { APP_ROUTER_PROVIDERS } from './app.routes';
import { Location, LocationStrategy, HashLocationStrategy} from '@angular/common';
bootstrap(AppComponent, [
APP_ROUTER_PROVIDERS,
HTTP_PROVIDERS,
{provide: LocationStrategy, useClass: HashLocationStrategy}
]);