Synergy - Cross-platform software for sharing your mouse and keyboard between multiple computers
Typeeto - Use Mac’s keyboard to type on iPad, iPhone, Android, etc.
Input Director - Control multiple windows systems with one keyboard/mouse. Share a keyboard and mouse across multiple windows system.
1keyboard - Type on your iPhone, iPad or AppleTV using your Mac keyboard
Ultramon - UltraMon is a piece of software built to help with the management of multiple screens on the same computer system. Without software like this, taking full advantage of an expanded desktop space can be difficult.
KeyWi - Use your computer's keyboard to type on your iPhone or iPad