As a traveller, I carry multiple photocopies of all critical documents (passport, credit cards, driver’s license, tickets, itinerary, etc.) In addition to the paper copies, I also store a copy of these documents on one of my online storage services just in case.
There are dozens of online storage service providers but the most popular are the likes of Dropbox, and Box.net. Unfortunately most of these services charge a premium price when the cost of storage is dropping like a rock so imagine my excitement when the Wall Street Journal reported that Google would soon release its long rumored Google Drive service. Although information is questionable at best, we can assume that if Google does launch this type of service, it will offer plenty of free storage and additional storage at a much more competitive price than its competitors (plus you can expect integration with the other Google properties G+, Google Docs, Picasa, etc).
WSJ says soon may mean weeks or months... So you need patience, patience, patience.