Ubuntu :: Write Access On Raid5 Mount And Network Access

I'm running ubuntu 9.10, and created a softraid5 with no problems. Now i need it to automount with user read/write access, and i need to make some network share folders. My fstab has the following line for the raid:

Code:
/dev/md0 /media/raid auto rw,user,auto,exec 0 0
After i mounted it, i changed the permission with:

Code:
sudo chmod 777 /media/raid/
So now i can create folders and files on it.
Then i created some shares, one with guest access and other with no guest access.

Now the questions:

1) If i access the guest shared folder via WinXP, i create files and folders, but they appear locked on ubuntu, so i cant access them until i change the permissions. If i go to proprieties/Permissions, the owner is "nobody".

2) What password do i need to use on WinXP, and i try to access the non-guest shared folded? Do i need to create a user just for that?