Creating a comma separated list for unique entires

Please let me know how I can achieve the following:

I have this:

NAME	STATE
BOB	PA
BOB	NJ
BOB	DE
TOM	PA
TOM	DE

I need to have this:

NAME	STATE
BOB	PA, NJ, DE
TOM	PA, DE

I have to do this on a very large scale and doing it manually is just not an option... any ideas would be greatly appreciated.

Thanks!