You can give a shot to PartedMagic. It's a linux livecd for the sole purpose of partition manipulation.

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I have used it to manipulate HDD with WinXP NTFS partitions without issues. As long as you do not resize your Vista partition, I think it should work fine with Vista too.

BTW, my understanding is that you don't 3rd party software to resize Vista partitions. The below were steps i found quite some time ago on the net for resizing Vista partitions

1>Click on the Start menu
2>Right click on Computer and click on Manage
3>In left pane, open Storage category and click on Disk
Management
4>Now Right click on the partition you'd like to modify.
5>Click on Extend Volume or Shrink Volume to extend or
shrink the selected partition to desired size