There are multiple ways. You can use a 3rd party product like XoSoft or DoubleTake. Another option could be to nightly dump your database within SQL to a centralized location where the spare server can nightly copy to a local volume for “future” use.
Another option via <a href=”http://sqldump.sourceforge.net/ “>Open Source</a>
You can use database mirroring to keep the backup machine in sync in near real time.