Cloud printing sounds like another way of asking someone to marry you by getting a pilot to write your proposal in the sky, but it's actually the latest aspect of Google's upcoming Chrome OS platform. Answering the question of how the netbook/tablet platform would handle printing from cloud-based apps, Google Cloud Print basically acts as an intermediary for a network-connected printer.
Google envisage either a new generation of "cloud aware" printers being produced by hardware manufacturers, or that users will network-enable existing printers either by sharing them from an attached computer or by using some sort of Print Proxy gateway device. Applications on Google Chrome OS would then send their documents off via Google Cloud Print and have them shuttled to the printer of their choice; that could be a in an office on the other side of the world, or a printer on the other side of your desk.
Interesting, while this is being billed as a solution for Google Chrome OS, the system would also work for smartphones and other devices. Google have already published the early APIs for developers - together with hardware manufacturers - to take a look at.