Time Capsule is a wireless backup system for the Mac that backs up drives to an
external device, supplied by Apple of course. It is both software and hardware.
TimeMachine is a utility that does backups and Restore in Apple OS.

There are Linux equivalents that will backup drives to an external device at
pre-set intervals or on demand. Just search the net and you will find more
options than you can imagine. There is a wide range of options, some easy and
some more difficult depending on how your view things. Easy for some people is
the commandline and for others it is the GUI approach.

You can use Google's Flyback as an equivalent to TimeMachine which is an Apple
backup and Restore utility. This is for Ubuntu 7.10, but should work with 8.04:
www.howtoforge.com/...ups-with-flyback-ubuntu-7.10

Also:
bernaz.wordpress.com/.../flyback-a-time-machine-backup-utility-for\
-linux/

I have used Flyback and it is easy to use and not hard to get up and running,
especially if you have Java JRE installed already.

There are free applications such as: http://www.rsnapshot.org/ and konserve
which is in the repositories and part of KDE.

There are commercial apps such as: http://www.handybackup.net/linux-backup.shtml
and http://www.desktoplinux.com/news/NS2461279608.html

For businesses:
http://searchstorage.techtarget.com/news/article/0,289142,sid5_gci1121697,00.htm\
l?adg=298690&bucket=NEWS

See more options here: http://www.debianhelp.co.uk/backuptools1.htm

You can also do it from the commandline, if that is your thing:
http://www.halfgaar.net/backing-up-unix

The original poster can let us know more about what she had in mind and people
can share their experiences. Coming from Apple she would probably prefer the GUI
approach, but I don't know her preference re: this.

If it is just a matter of getting the hardware working, then she may want this:
talkback.zdnet.com/5208-12353-0.html\
98828&start=0

There are two links in this brief article that I did not explore. You won't get
any help from Apple as they see Linux as the enemy and do all they can to ignore
their free, open source cousin.

She also might want to check out: http://thebadapples.info/ which is a Linux
podcast dedicated to Mac users. It has lots of useful info and if you email
Klaatu the podcaster, I am sure he would be able to help and even feature Time
Capsule if you request it. He also has a blog at:
www.binrev.com/forums/blog/xklaatux/index.php?