If you need access to your Windows, Mac, or Linux computer from an Android, iPhone, or iPad mobile device you can use the free program TeamViewer. TeamViewer lets you access any of your computers which have the host application installed, from any computer or device running the client app. They also have a flash-based option you can use by logging in to their website.
To set up TeamViewer, begin by creating an account and installing either the full version (both client and host app) or just the host application on any computer(s) you would like to access remotely (download link). You can enter your TeamViewer account information during Unattended Access Setup so that you can easily sign in and access your computer from multiple devices.
Now install the appropriate client app for the device you would like to access your computer from. Enter your TeamViewer account information to connect and see a list of your available computers. Just make sure to leave the host app running on your computer and that it is not set to automatically go in to sleep/hibernate mode.