I haven't used Redhat before, but I think I know how to get you Linux distribution running.
Firstly, you need to make sure that you have enough Hard Disk space to install it on. A whole HD for Linux would be nicer and better, but if you only have one which will be shared then you need to create some space for Linux to install on. This is the most dangerous part when trying to install Linux. I would recommend backing up all essential files from windows to a seperate media (i.e. CDROM, zip drive). To create the space you need to use something like FIPS or Partiton Magic. I cant help much more on that because I have a whole HD for Linux. I'm sure someone else can help you with that.
Assuming you have enough space to install it on you then need to boot up with the Redhat CD in the drive. If your BIOS doesn't support cd drive boot then you need to make a boot floppy. The documentation on the cd should tell you how. Assuming you that the cd boots up you can then install Linux
Somebody who has installed Redhat 6.1 will be able to tell you about the install process better than me beacuse I haven't used it. However I do know that it will ask you about installing LILO into the master boot record.LILO allows you boot any OS on you PC. I would say yes if it does not allow you to make a boot floppy, otherwise you wont be able to boot up Linux.
There is so much you have to know before you can load it up without any trouble, so I would look at http://www.linuxdoc.org
for more informatiom on Linux itself.