I migrated most of the infrastructure I work on to vSphere 4.0 last year and since then have live-resized a fair few disks as needed. For most of these it was the data partition that was increasing so it was a quick case of growing the vmdk, then loading up diskpart in the VM, selecting the partition, and typing extend.
I was recently shown a fantastic tool for this purpose – Extpart, which is made by Dell. Amazingly, it’s seven whole years old! If you read this, help spread the word.
If you’re on a 64bit machine you’ll find that it refuses to run. The .exe on the Dell site is actually a self-extracting zip file, not the tool itself. Use an archiver (7-Zip, WinRAR, etc.) and you’ll be able to extract it.