We also posted it in the sticky at the top of the forum:
Hope this helps.
Microsoft released SP1 for Vista today to OEM's to include on their machines, expecting it starts to appear on the market in March or April. Approximately around that time Vista including SP1 will be sold in the shops as a boxed product.
Enterprise customers will receive Vista SP1 in early March.
For all of the current Vista users this is the planning:
"We are planning to make SP1 available for current Windows Vista users on the following schedule: