I closely paralleled the approach taken in how-to-use-moment-js-library-in-angular-2-typescript-app but still get error TS2307: Cannot find module 'mqtt'. 
npm install --save mqtt
<s>typings install --save mqtt</s
that didn't find the typings but this did...
typings install mqtt --save --ambient 
my tsconfig.conf looks like this
{
    "compilerOptions": {
        "noImplicitAny": true,
        "module": "commonjs",
        "target": "ES5",
        "emitDecoratorMetadata": true,
        "experimentalDecorators": true,
        "sourceMap": true,
        "declaration": true
    },
    "files": [
        "ng2-mqtt.ts"
    ],
    "exclude": [
        "node_modules"
    ]
}
and ng2-mqtt.ts just has this...
export * from './src/mqtt.service'
and ./src/mqtt.service.ts has..
import {Injectable} from 'angular2/core';
import * as mqtt from 'mqtt';
@Injectable() 
export class MqttService {
  constructor() {
     //mqtt.connect('ws://10.0.1.100:3333')
     // ...
  }
}
tsc -version 1.8.10, angular2@2.0.0-beta.17, typings 0.8.1, npm 2.14.20, node v4.4.1, Windows 7
Is it just going to be too hard to use Angular 2 with elements outside of its typescripted world?