Once setup, Mozy automatically makes an offsite backup of any data you select. The data is encrypted before leaving your PC (using 448-bit Blowfish encryption) and can only be viewed again using your password (that you define). If you have a PC failure you can easily restore your backed up files onto another PC (by downloading the backup or requesting DVDs of the data). If you require more than 2GBytes of data backed up you can get unlimited data backed up for $4.95 per month.
We have been using this at Mole End for over a year and are very happy with it!