A good place to look up fonts is http://www.google.com/fonts
Perhaps you can download Droid Sans from here: http://www.fontsquirrel.com/fonts/Droid-Sans if TTF is ok with you.
As for the font, if you wan the font to be global, you can simply do:
@font-face {
font-family: DroidSans;
src: url('location/DroidSans.ttf'),
url('location/DroidSans.eot'); /* IE9 */
}
html * {
font-family: DroidSans;
}
If you want to support IE9 - I think there are plenty of ttf to eot converters online.