Well, after a bit of work, I found two things that work pretty good. Windows has a 3rd party driver to read Ext2 that you can get from http://www.fs-driver.org/ haven't had any problems. Think so, but not sure as I'm writing this, but believe it'll work with ext3 too. It should anyway, as they're pretty much the same thing (just logging added). But it doesn't explicitly say it. This basically just allows windows to read those drives. So there's no opening a separate program, works right in windows explorer.
Second, I used the NTFS-3G driver for linux. Requires to have fuse installed. Didn't require anything on my part except to make sure fuse was enabled in my kernel, and in Gentoo to do a emerge ntfs-3g. From there, you just mount the drive as a filesystem as type ntfs-3g. Have done some read-write on it and no problems. I set it up in my fstab, and just changed the 'ntfs' parameter for that drive to 'ntfs-3g'. works like a charm.
In the end, I'll probably keep all my shared drives as NTFS. That way if I'm taking my external, i can use it on another person's computer who may not have the ext2 driver installed.
Good stuff.