This is going to be my first atempt at a slackware install so what I want to do is have a duel boot system with windowsXP ( as much as I want to just have a slack ware system, I have to share my computer with someone who does not want to learn slackware)and I don’t know how to setup my partitions for both windows xp and slackware. I have a 80GB hard drive and I would like to have windows xp take up half of the hard drive and the rest to slackware. I am concerned that I will screw something up because I have never had to create any partitions before.

Typically, I use the GParted Live CD to create/resize partitions.

If you don't already have XP installed, I would do the followingI make a separate boot partition so that if I ever delete linux, I can still boot windows using the linux bootloader (I use grub). Note that you can only have 4 primary partitions, so really the swap and ext3 partition will be on a logical partition.

If windows is installed already and you don't want to reload it, boot into safe mode, disable virtual memory and defrag the drive. Then GParted can just resize it. Then you can put boot as the third drive and keep your windows drives together.

Ok now which partition is windows installed into and which slackware, also will I have any security problems with slackware because windows is installed on the same hard drive?

Windows goes on the NTFS partition (in my example /dev/hda2). Slackware's /boot partition would go on /dev/hda1, and the / partition would go on /dev/hda5. The installer should find the swap partition and use it.

You shouldn't have any security issues with Windows being installed on the same drive. However, if you store a virus infected file, say a piece of shareware on the fat32 partition, you could email that file to someone and they could be infected. But in general, windows security vulnerabilities don't affect linux since Windows isn't running at the same time as linux.

what partitions should I create when I install windows and which ones should I create when I intall slackware? I have also read somewhere that swap should be the size of the amount of ram you have is that true

Clarification: The last primary partition,/dev/hda4, would be consumed in making the logical partitions. So swap would actually be /dev/hda5 and the rest of the drive would be /dev/hda6.

Your scheme will show up as:
/dev/hda1 /boot 100MB
/dev/hda2 NTFS 20GB
/dev/hda3 Fat32 20GB <-- for shared files between linux and windows
/dev/hda5 swap 512MB
/dev/hda6 ext3 rest of drive <-- for linux

I recommend creating them all ahead of time using GParted. Then just point the XP installer to /dev/hda2 (I forget what the second drive is called in the windows installer -- it's been a long time since I installed windows). Similarly, you just have to point slack at the other partitions it needs. Each will probably reformat the partitions, but at least they're already sized...