A really hot FAQ is:
How can I enlarge a default 4GB virtual disk in a VM?
Usually answer is:
1. Create a secondary virtual disk (larger than first one)
2. Grab a program like Symantec Ghost
3. Clone VHD1 inside VHD2
4. Remove VHD1 and go happy with larger virtual disk
This solution is good, but Ghost (or DriveImage or Altiris products) are expensive.
I just found a free tool tha is OS indipendent, fits in a single floppy and clone a disk from smaller to larger dimension.
It’s called HDClone Free Edition.