I believe that now (alpha.35 and 36) is needed to be:

import {Http} from 'http/http';

Remember to add (since now is a separate file) the reference in your html: https://code.angularjs.org/2.0.0-alpha.36/http.dev.js

1. We are working on a separate data persistence layer, that will cover HTTP. This is not finished yet.
2. Because of Zone in Angular 2 you can use any existing mechanism for fetching data. This includes XMLHttpRequest, fetch() and any other third party libraries.
3. XHR in the compiler is meant to be private, and we can change the API at any time and as such should not be used.

Last update: Jul 27, 2015

Angular version: 2.0.0-alpha.32

Typescript version: 1.5.3

A simple example of how to use the Http module with Observable:

app.ts:

import {Component, View, coreDirectives} from 'angular2/angular2';
import {QuestionApi} from '../data/questionApi';

@Component({
  selector: 'app',
  viewInjector: [QuestionApi]
})
@View({
  directives: [coreDirectives],
  template: `
  <div *ng-if="questions">
    {{questions | json}}
  </div>
  `
})

export class App {
  questions;

  constructor(public questionApi: QuestionApi) {
    questionApi.getQuestions().subscribe(res => this.questions = res);
    questionApi.getQuestionsFeed().subscribe(res => console.log(res));
    questionApi.createQuestion({'foo': 'bar'});
  }
}

questionApi.ts:

import {Injectable, bind} from 'angular2/di';
import {Http, Headers} from 'angular2/http';
import {Observable} from 'rx';
import * as io from 'socket.io-client';

@Injectable()
export class QuestionApi {
  constructor(public http: Http) {
  }

  // Get request and serialize the result to JSON
  getQuestions() {
    return this.http.get('http://localhost:3333/api/questions/')
      .toRx()
      .map(res => res.json());
  }

  // Post request with Headers
  createQuestion(question) {
    return this.http.post('http://localhost:3333/api/questions/',
      JSON.stringify(question),
      {
        headers: new Headers({
          'Content-Type': 'application/json'
        })
      })
      .toRx()
      .map(res => res.json());
  }

  // Create an Observable from event
  getQuestionsFeed() {
    var socket = io('http://localhost:3333');
    return Observable
      .fromEvent(socket, 'questions:feed')
      .map(res => JSON.parse(res));
  }
}

Its already in angular2, so you dont need to put anything in package.json

You just have to import and inject it like this. (this is a Stuff service with a methodThatUsesHttp() that just logs the response)

import {XHR} from 'angular2/src/core/compiler/xhr/xhr';

export class Stuff {
    $http;
    constructor($http: XHR) {
        this.$http = $http;
    }

    methodThatUsesHttp() {
        var url = 'http://www.json-generator.com/api/json/get/cfgqzSXcVu?indent=2';

        this.$http.get(url).then(function(res) {
            console.log(res);
        }, function(err) {
            console.log(err);
        });
    }
}

In version 37 you need to do this:

///<reference path="typings/angular2/http.d.ts"/>    
import {Http} from "angular2/http";

And run this tsd command:

tsd install angular2/http

A simple example using the http module:

import {Component, View, bootstrap, bind, NgFor} from 'angular2/angular2';
import {Http, HTTP_BINDINGS} from 'angular2/http'

@Component({
   selector: 'app'
})

@View({
    templateUrl: 'devices.html',
    directives: [NgFor]
})

export class App {
    devices: any;
    constructor(http: Http) {
        this.devices = []; 
        http.get('./devices.json').toRx().subscribe(res => this.devices = res.json());
    }
}

bootstrap(App,[HTTP_BINDINGS]);

You can have the complete working app here: https://github.com/kaalpurush/ng2-http