Yeah, RedHat can read from NTFS partition as well. Might need a kernel recompile...I'm not quite sure.
RedHat also tends to have a more wizard-based approach to configuring the system. Slack tends to involve config file editing a lot more often. Whether this is good or bad is a matter of personal preference really.
Yes, you need to enable support for mounting NTFS partitions when you compile the kernel, that is all you really need to build in support for NTFS on Redhat. I'm not even sure if the kernel that comes with Slackware 10 even has support for NTFS built in.
you can't use make oldconfig with different version like 2.4.x kernels and 2.6.x kernels. I've always had problems with it, only takes about 10 minutes to config a kernel after you know what you are doing