I have cloned my 40GB HDD to my 320GB HDD via
dd and now I am wondering how can I expand the 34GB NTFS partition to include the unused 260GB of free space? Thanks :)
Move the intervening partition to the right i.e. end of the drive and then you can expand the 34GB partition once it is adjacent to the unallocated space.
You should still be able to boot into Windows. Worst-case, you might have to run Startup Repair from the Windows DVD, and then Boot Repair from a Ubuntu LiveCD.