Justin Fox and Kevin Gallagher have both done breakdowns of the global stimulus effort by nation. The most striking thing, as Justin notes, is the wide variation: the plans vary from about 7% of GDP (China) to .3% (Italy). There is clearly a coordination problem here; Justin says that most of the developed world is not doing its part.
Indeed, some of the developed world is actively undermining any kind of coordinated global stimulus. Ireland, for example, is slashing their public spending by an amount larger than some other countries' stimulus plans. This isn't malicious (Ireland has truly crappy public finances, after all), but those cuts in public spending are part of the global stimulus calculations.