Interestingly, NY Times writer David M. Herszenhorn acknowledges that the stimulus will "trickle" into paychecks (as much as $14 a week if you make $75K) and then leaps to the conclusion that a Congressional stimulus "will start to be felt within weeks once the final version becomes law."
If you are unemployed, your benefits would be extended and increased up to $25 a week. If you qualify for foodstamps, you might get up to $79 more a month. Neither of these will stimulate jobs, although its possible that the foodstamp program expansion will help retain some.
One-third of the package is tax cuts: $275 billion. Herszenhorn does not explain (or cite a source for) his assessment that tax cuts will have the "swiftest impact." Just take his word for it. Oh, and last week, the Congressional Budget Office "found that only about $136 billion of the $355 billion that House leaders want to allocate to infrastructure and other so-called discretionary programs would be spent by Oct. 1, 2010." The Obama White House disagreed.
As a reminder of the size of the sums involved, $819 billion is about $10,250 for every family in the U.S. That's what the House wants to borrow on your behalf, because the U.S. government does not have this money. It has to borrow it, by selling government securities.