To manually check for an update -
Plug Focus into PC
Load Zune software
Click Settings
Click on the "Phone" tab
Click "Update"
To continue checking, just keep going back to the Zune desktop, then going back through settings to the "Update" page.
There is no way to force any update.
There is no ETA on an update as even though Microsoft has promised the update by the 12th, that was just for the carriers, and they have made no promises for a timeline for the update to be in our hands. It could be as late as next year, depending on when another update is scheduled, yer carrier, yer phone, etc.
I'm assuming you have AT&T, and they (nor any carrier) are obligated to give you the NoDo update until a day before the NEXT patch is released to carriers.. and as of right now, the only other patch we know of is Mango, and I think we have a better chance of seeing pigs fly than seeing Mango in 2011.