Ars Technica has pointed out that Apple is now offering a "no fee" license to anyone interested in developing products that use Mini DisplayPort.
Apple first introduced Mini DisplayPort – which is a modified spec of the original DisplayPort – on the new MacBook and MacBook Pro notebooks. Apple is also using Mini DisplayPort on the 24-inch LED Cinema Display.
The availability of a license confirms that the port is propriety from Apple but should allow third-party developers to make adapters to allow notebooks with VGA and DVI connections to use the new 24-inch LED Cinema Display.