I searched, and didn't find anything about this subject. I already asked one linux forum specific to my distro, and got no replies.

I'm thinking about reformatting my Linux (I kinda messed it up big time). So this is more for future reference. Is there something in Linux that's like Windows XP's system restore feature?

Well, I'd say, depends on your distribution (which one is it?). On Debian, you can reinstall packages.
What specific problems do you have? May be we can help you (if your decision to wipe your hard disk isn't final yet).

If you are starting over there are some things you can take into account to save yourself the hassle of doing a system restore in the future. I highly recommend a separate /home partition. This combined with keeping good notes to yourself on what you install and how makes reformatting a relatively simple task as you will loose no personal data. You may also want to keep a dir in your $HOME folder with all of the changes you make to configuration files on your computer. For instance I have made a lot of changes to my httpd.conf (apache configuration) file and so I always keep the most up to date copy in my backup folder so when I reformat I don't have to start from scratch.

why cant you just save any important files or folders you have and re-install?

One way that I accomplish "system restore" is to burn a CD-ROM of the material in the /bin, /usr, /etc, /lib directories. This gives you the ability to recover most things, and to do so from a known-good source.

It is also very helpful to have a second hard-disk drive .. or even a third and a fourth. Storage is cheap these days and the flexibility that it gives you is enormous. If you don't have room inside the box, spend $50 or so for a nice FireWire + USB 2.0 card. Now an external disk can be purchased that will happily run at internal-disk-drive speeds (or even faster). Some of them will fit in your pocket, or (hint, hint...) in a safe-deposit box.

If space is simply not an issue, you can create an on-disk copy of these essential directories, locking them away in an obscure place and read-only. When you do a system update of any kind, you can restore the system back to a known state.

Using the "test machine that you don't give a hoot if you crash," practice this...

IMHO you shouldn't backup directories containing only material which can simply be reinstalled; /bin, /usr and /lib do not contain configuration or "user-made" data, so if they are lost, you can simply reinstall the affected packages and nothing is gone. /usr alone takes on my system about 2 GiB - do not waste your time or your backup media (especially if you use CDs) with data which does not need to be backed up.
I wrote a backup script that backs up /boot, /home, /etc and /var, and before burning the CDs, it creates a list of all files on the system, and writes it to a file in /var/log. It can be very useful to have such a list in case you need to know which files you ought to have, believe me.