"... how many people living in the US know how to make gunpowder from scratch? Given enough time, I guess I could build a ... How would you survive if suddenly transported back to 1000 AD? ..."Well I'd hope I'd be pushed forward a few hundred years into the late 12'th - early 13th century and dropped into Western Europe. The UK or France.
Why late 12th/early 13th century France or UK?
Well for one thing the "Hundred Years' War" is just starting and it probably is the most turbulent time in UK/French history and with this comes warfare and opportunity. It turns out this period of history is where the linage of the French House of Capet was broken and King of England (John - Henry III) had gone from owning more land than the King of France to loosing almost the lot.
The consequences of these new weapons meant
that the nobility was no longer the deciding
factor in battle; peasants armed with longbows
or firearms could gain access to the power,
rewards, and prestige once reserved only for
knights who bore arms.
But these were heady days for the English this is the time of the Longbow (
and by the way the 2 fingered salute favoured by those of English descent and a token to their weapons superiority ), the introduction of the cannon and the end of the era of chivalry, the introduction of Modern army, the introduction of the Magna Carta some 50-100 years prior, centralised government that had the authority to raise taxes & armies. So in terms of making your mark this was the era.
The first problem you'd have is language. I'd either have to bring a book (latin) or wing it on my language skills but where to learn latin? Anything but a classical education makes me stand out as an uneducated heathen. As for a job if you are fit enough you could either join up as a foot soldier but a more lucrative path might be to hack the warfare technology of the time and work on improving them. One problem at the time was training enough archers to use the longbow efficiently. It took a lot of training from an early age - all English boys from the age of 12 years had to train to use the longbow & all men from the ages of 15-60 carried such weapons.
I'd be looking out for Yeoman ~ http://en.wikipedia.org/wiki/Yeoman#Middle_Ages