So I finally made the plunge and switched over to Mac! And I love it! Except for the part where it is telling me that I can only read from my external hard-drives, not write to them. Is there a setting that I am missing, or do I need to reformat the drive? I really hope that I don't have to reformat! Thanks so much to anyone that can help!

If the drive is formatted in NTFS then you can only read from it.

No worries, I'd just pull everything to your Mac temporarily, format the external drive and then put it back on the external (if you have the room).

I believe the permissions on all of your files on your external disk are set to "read only"

ctrl+click (right-click for the windows folks) on a file or folder and select "get info"

scroll down to "ownership and permissions"
change to read & write.

if the drive is NTFS it might be a good idea to reformat at some point and change to "mac osx journaled" but check with someone more knowledgeable than me before doing that.

if you do decide you need to reformat you will use Disk utility to do that. it is found here:
applications/utilities/disk utility

select external drive from list on left.
check what it says for "format" on the bottom of the window.

Thanks guys - I have tried the disk utilities thing to no avail. If I reformat it, will my windows laptop be able to read from it or is it an either/or sort of thing?

depends on how you reformat it.

Mac can read NTFS but not write to it

Mac can read and write to Ms-dos file system (aka fat 32/16)

Mac can read and write to Mac OS journaled and non journaled (aka HFS)

Windows can read and write to NTFS

Windows can read and write to Ms-dos file system

Windows can NOT see Mac os journaled and non journaled (can with software called macdrive)

** I format all mine as Mac os journaled... I'll let Damon, Bryce, or someone else explain the speed differences to ya***