Computer back-up service CrashPlan, is offering a special Christmas deal, potentially worth up to $179.97, around £110.

CrashPlan lets you back up your computer to a local drive or another computer anywhere in the world and is billed as easy, automatic backup that works quietly in the background.

The basic version of CrashPlan is free for non-comercial use.

CrashPlan Central adds unlimited online backup to CrashPlan for a yearly fee.

CrashPlan+ is an upgrade to CrashPlan that adds continuous, real-time backup, removes ads and provides priority customer support. It costs $59.99.

CrashPlan are offering CrashPlan+ free for those who sign up for the monthly plan.

"Holiday Special - We're giving away CrashPlan+ ($60 value) with every CrashPlan Central subscription through December 31st!," runs the Christmas promo.

Families can get up to three CrashPlan Upgrades when they subscribe to a Family Unilimited Plan, a saving of $179.97.

CrashPlan is compatible with Mac, PC and Linux and Open Solaris machines.

Mac specs are Mac OS X 10.4/10.5/10.6, G4/G5/Intel CPU, 1GB+ memory, 50MB+ free drive space.

Full details can be found at www.crashplan.com.