You can install the FTP service on Windows 2008 R2 as followed:

1. Go to the Start menu, click on Administrative Tools and then click on Server Manager
2. In Server Manager Pane, find the Roles Summary section and click on Web Server (IIS)
3. In the Web Server (IIS) section, click on Add Role Services
4. Under Role Services, select FTP Publishing Service. This will install the FTP service + the FTP management console
5. Click Next and then click on Install

The FTP service will now be installed; all you have to do is wait for it to finish.