Pooped my pants a little. I wonder how many Bitcoins they hold (held?) in their many, many wallets.
Calm down. "They" is actually "him". He is not very likely to run with your measly bitcents.
It was always clearly stated by instawallet that it is a "fun" project, not a venture for profit.
"Instawallet is not a bank", so you should not have used it to store larger assets with it anyway.
Wait until it comes back up, withdraw the majority of your assets and leave only what you are willing to / can afford to lose.
It is a highly useful service and a great contribution to the community, but always keep in mind:
instawallet.org is not a bank