I've also posted this over at the o/c forums. Figured someone over might get some use from it:

Back when I first installed linux, I was most afraid of the dual boot setup, and didn't like the idea of possibly trashing my drive. After doing it, I realize how easy and straightforward the process really is. So I'm posting this info to guide our newbs out there and dispell your concerns about dual booting. (I assume we already have windows installed and working).

Step 1: Partitioning

OSes don't like to share partitions. In the case of Linux and a M$ OS, they need to be formatted with different filesystems. Generally linux uses ext2 or ext3, and windows uses either FAT32 or NTFS. Therefore, we need to set up different partitions for each OS. This is the most important step, and we must plan it out carefully, lest we need to wipe the drive later. Most of you will have one big partition occupying the whole drive, or at least the entire drive formatted with windows partitions. You have two options here: pay $70 for partition magic and resize your partitions, or start over. I personally choose to start over, but thats cause I have no money. If you want to try Partition Magic, heres some linkage:
http://www.powerquest.com/partitionmagic/
Now, lets figure out how much space we need for linux. We will want at least two seperate partitions, one root and one swap. The root partition is used to store the OS files, programs and possibly your data as well. The swap partition is similar to the windows swap file; it emulates RAM if your memory fills up. I've found that if you have a reasonably spacious drive, its nice to allocate about 10 gigs for linux, this way you will have plenty of room in the future.

Now that we know how much space we need, lets open up some space on the drive. Either resize your current partitions with Partition Magic, or wipe the drive and make them anew. It is important that we leave the space we want to put linux on as unallocated space, in other words, in no partition at all. The partition will be created during the install.

A quick note: The bootloader you chose (I will get to this later) may affect your partitioning plan. Some distros only include LILO (because GRUB is not 'officialy' stable). If you plan to use LILO, keep in mind it is unable to boot off over partitions located above the 1023rd cylinder (aprox the 8 gig mark).

Another note: The filesystem you use for you windows partitions is also important. Linux can read and write FAT32 with no problem. However, it can only read NTFS (and usually requires a kernel recompile to do so). Keep this in mind if you wish to access your windows files from linux. (As far as I know, there is no way to see linux partitions from windows).

Step 2: The Install

Now, we have our partitions as we want them, and the area linux will go into is unallocated space. Its time to begin the install. Many distros boot off a cd, some off a floppy, inorder to begin the installion process. The "newbish" distros like Red Hat, Mandrake, etc have very user friendly installions. Red Hat even offers to partition automatically for you. You will need a root partition and a swap partition. Format your root partition in ext2 or ext3 (preferably ext3) and set the mount point to /. Format the swap in swap filesystem (there is no mount point for swap). Consult your distros documentation for more install info.

Step 3: Bootloader

At some point in the install, you will be asked to install a bootloader. Do some research beforehand on which one is best for you. Your choices will be either GRUB or LILO. I prefer GRUB because it has a few less restrictions than LILO, but either one will work. In the bootloader configuration, you will have to tell it which partitons you want to boot off of. For example, if my windows install is on my first partition (/dev/hda1/) and my linux install is on my second (/dev/hda2), I would have to give this information to the bootloader so that it knows what to do when you boot the machine. The newbish distros will have a very straightforward way of specifying these parameters.

You also have to choose where to install the bootloader. Your choices generally will be either the partition where linux is installed, or the master boot record (MBR). You will usually want the MBR, so that it boots directly off of your linux bootloader.

That's it. When the install completes and you reboot your system, you should see the linux bootloader. Check to make sure you boot into both windows and linux successfully. If you can, congratulations on a good well done. If you can't don't panic. If linux works but windows does not, you can probably fix the problem via the linux install. If windows works and linux doesn't, you may have to reinstall, hopefully finding and correcting the problem before. If windows does not work and you must get into windows for some reason, booting off a dos boot disk and running fdisk /mbr will erase the bootloader so you can boot straight into windows.

Heres some general information:
http://www.redhat.com/docs/manuals/...de/ch-grub.html
http://www.linuxjournal.com/article.php?sid=4622
http://www.acm.uiuc.edu/workshops/l...stall/lilo.html
http://www.linuxgazette.com/issue38/veselosky.html
http://linux902.tripod.com/dualboot-choosing.html
http://www.techtv.com/screensavers/...3397093,00.html
http://www.xminc.com/linux/WindowsXPGrubMandrake82.html

If I've left anything important out, or there are any mistakes, please notify me and I will fix them. Hopefully this can help some of you out there.