partitioning
 

Hi, whats the recommended way to partition a 40GB HDD for Redhat linux?

What version of RedHat Linux? If you have RedHat Linux 9, drop it, and move on with a newer version. The Linux world of new releases, is a lot different than OSX or Windows.

New Windows Release = 3 years to almost a decade.
Linux = a month or two.

Get yourself a copy of Ubuntu Feisty Faun(?spelling?). It will complete your life.
Gentoo if you want to control how you complete your life. (CAUTION GIVEN)

If you still want to go with whatever version of RedHat you have (if it isn't 9 or older, than it must be RH Desktop or one of those newer RedHat products that cost something), than just use however RedHat partitions your drive. But most any distrobution does the same.

regardless of what distro you choose, my advice on partitioning is "KISS".

With 40GB dedicated to Linux, I would have 6GB for the OS and apps, a 20GB data partition (mount at /home), 1GB swap, and the rest left unpartitioned for future growth.

The simplest partitioning scheme would be to create a 1GB swap and then a single partition of whatever file system you prefer (reiser, ext3, etc...) in a reasonable size of 20GB for the OS itself. If everything including /home is in this partition you won't run into any problems.

You can create a separate /home partition as pixellany described if you choose, and it does make upgrading or distro changes a little easier, but it isn't absolutely necessary. That said, that's what I normally do.

There is no straight answer to this, if there was, then the partitioning would be done automatically by your distro. It really depends on how you are going to be using your pc. If you are going to have it with many users, then you would want a bigger /home partition than you would if only you are using it or if you are going to be saving a lot of videos, then also you would want a bigger /home partition. If you are using it as a web server, then maybe a bigger/separate /var/log partition.
It all depends on your use.