1. First, on your Macintosh computer, download the latest version of Microsoft Remote Desktop Connection Client for Mac. It can be found here.
2. Next, you must allow remote connections on your Windows computer. Select which version of Windows your PC is running below.
3. On your Macintosh, open Remote Desktop Connection.
4. In the Computer field, enter the name of the Windows computer and click Connect.
5. Enter your user name, password, and domain for the Windows computer, if necessary.
How to allow remote connections on Windows XP:
1. You must be signed in to an administrator account.
2. Click Start -> Control Panel -> switch to Category view.
3. Click Performance and Maintenance -> System.
4. Under the Remote tab, enable the Allow users to connect remotely to this computer check box.
5. Click Select Remote Users.
6. Verify that your user account is listed. If it is not, add another user account by clicking Add and typing in the user account name that you want.
7. Close the Control Panel windows and go to the Start menu. Right-click My Computer and go toProperties. Note down the full computer name under the Computer Name tab.
How to allow remote connections on Windows Vista:
1. You must be signed in to an administrator account.
2. Click Start -> Control Panel -> switch to Category view.
3. Click System and Maintenance -> System.
4. In the Navigation pane, click Remote Settings. Under Remote Desktop, select the option that you want. This may require a username and password.
5. Click Select Users.
6. Verify that your user account is listed. If it is not, add another user account by clicking Add and typing in the user account name that you want.
7. Close the Control Panel windows and go to the Start menu. Click Control Panel. Under System and Maintenance, click System. Click Computer, domain, and workgroup settings, then note down the computer name.
How to allow remote connections on Windows 7:
1. You must be signed in to an administrator account.
2. Click Start -> Control Panel -> switch to Category view.
3. Click System and Security -> System.
4. Under System, click Allow remote access.
5. Under Remote Desktop, select the option that you want. This may require a username and password.
6. Click Select Users.
7. Verify that your user account is listed. If it is not, add another user account by clicking Add and typing in the user account name that you want.
8. Close the Control Panel windows and go to the Start menu. Click Control Panel. Under System and Maintenance, click System. Click Computer, domain, and workgroup settings, then note down the computer name.
Additional information and the full walkthrough can be found here.