Can i have all my different linux distros use the same Swap partition?

Ya sure. And its the right way of doing.
while installing the second distro, just point the swap to the earlier disto's swap.
regards

and since were on the same topic, I dont see anything wrong with the same boot partition eather. You will just need to create a new root partition.

Ya just one thing has to be kept in mind that the various vmlinuz/system.map etc. files should be renamed according to the distro so that they don't overwrite each other.

regards

What about my GRUB. I have GRUB loaded with options for loading Suse and windows, if I install another distro will grub be able to automatically pick up on it or how do i configure the additional distros to appear on my grub menu?

You can choose not to install a bootloader and then configure your Suse bootloader to boot the other Linux distros.

But no, GRUB will not automatically know it's there.

You could do something similar with the /home partition. For example, the /etc/passwd file indicates where a users home directory is, so for fedora-core you could have a home directory for user "vir3nt" be /home/vir3nt-fc and for SuSE be /home/vir3nt-su. It is the UID that is important, and not the actual name of the users home partition which is indicated by the $HOME variable and expanded with the "~/" characters.

If you share the /boot partition, then make sure that you only update grub or lilo from the same distro every time. You will need to manually edit the lilo.conf or menu.lst file when adding a new distro. The entry for you first distro can serve as a model.

You may have it configured so that /tmp is cleared everytime you reboot. That would be easy to share. Another candidate is /usr/local. The contents of the /usr/local hierarchal tree are left alone by the distros, so you can install shared tarball installations there. You may need to make sure that the paths are defined for each distro to use it, and check if any /etc/ files are installed when running the "make install" target. Running "find" with the -cmin option can help locate where all the new and modified files are located. Another option is to use "tee" to save the output of the "make install" phase.