There's a problem with some versions of the Inspiron bios (A20 to A28) so that it doesn't allocate enough memory to the graphics card. There's two methods of fixing this:
Best method - If you've still got windows on you're laptop download the A29 bios from Dell which fixes this problem. There is also a CD image which contains the bios update in case windows is not available.
Other method - There is a patch which fixes this problem called the 845patch which is available as an rpm.
The bios update is recommended by everyone in preference to the 845patch.
There is a website at http://www.geocities.com/randomnumbergenerator2001/
which documents installing Red Hat 9 , Fedora 1, Mandrake and Debian but most of the information on it applies to any distro (I'm now using Gentoo). This is by far the best guide I have seen when it comes to linux on the dell inspiron 1100.