USB hard drive read only access..

[WipeOut]

Hi,

I have just got a 500GB USB hard drive to do my backups to.. I was able 
to partition and format the drive (ext3)..

When re-plugging it in it auto mounted to /media/disk but it appears to 
be read only.. I am unable to copy files to it or create directories on it..

I have used USB flash drives in the past and have not had this problem...

Anyone know why the drive is read only and how to fix it?

Thanks..