AFAIK, there isn't any windows software to read ext* partitions. There is some NTFS reading support in linux, but I believe writing is a little big buggy.
Long story short, make an FAT partition that you share between linux and redhat on the same box. The FAT partition will show up as another drive in XP, and in linux, you can automount it someplace convenient, like /mnt/XPshare or something. If you're feeling adventurous, make it an NTFS partition instead and gamble with NTFS write support. Have fun!
