Unfortunately there is no HOWTO at fedora.redhat.com for this type of thing, nor is there a dual-boot HOWTO at www.fedorafaq.org
as of yet, but as I recall there is a warning after you click that option that says that all partitions will be deleted and all data lost.
I did find a HOWTO.. sortof... http://www.overclockersclub.com/guid..._fedora_xp.php
that HOWTO points to a Red Hat 9 dual-boot manual at http://www.redhat.com/docs/manuals/l...ot-parted.html
The latter link says to use a windows partitioning tool/util and to consult their documentation. The best to date is Partition Magic for M$ Windows, or there is partimage too.
What I'd do is back up all my data anyway because that's just a given in case the hard disk ever dies, or you get a virus or get hacked, etc. Then go for the partition magic deal, resize and follow the dual-boot howto.
Also.... there's a thread I posted here that has a link to a complete Fedora Core installation complete with screenshots even though the first link has 'screenshots' too you might want to check out the other one anyway and bookmark it, etc.