Glenn Fleishman explains a tiny tweak you can make in Lion that enables AirDrop peer-to-peer file exchange to work over local area Ethernet and wireless networks. This enables AirDrop for older Macs that lack the right Wi-Fi chips to work with AirDrop out of the box, and it also adds wired LAN access for even those Macs that do have supported Wi-Fi chips. follow link
Untrash the Trash
Feeling trasher's remorse? On Snow Leopard, you can open the Trash (click the Trash icon in the Dock) and "untrash" individual items there. Select one or more trashed items (files and folders) and choose File > Put Back. This returns the items to where they were when you originally put them in the trash. The keyboard shortcut is Command-Delete - the same as the shortcut for trashing an item in the first place, since in deleting something from the trash you are untrashing it.
Enable AirDrop for All Macs with Lion
Check out the Take Control ebooks that expand on the topic in this article: