I cheated. I did a Google search for the sign, which led me to a site where it described the best places to see the sign and take pictures. One of those sites had turn-by-turn directions. I followed the 101 to Barham Blvd, to Lake Hollywood Dr., to a couple of other streets (hey, do your own research) and was able to see the photo site from the satellite. I assumed the Hollywood sign was in the hills above the photo site, and zoomed in there. I never actually saw the sign in the satellite, but I must have been close enough.
According to what I think are the rules, I actually didn't cheat, because I started the game before I started the research, and lost some of the possible points because I took too long.
For the Vonage headquarters, I really cheated. I Googled the company and got the headquarters address, then I loaded my Street Atlas and did an address search and pinpointed the exact location before I ever started your game. Then, it was a simple matter of zooming to the correct location. Once I got there, the satellite picture made it obvious.
However you play it, I think your game has real value. I can see it as a fun way to teach geography, library science (as in reseach techniques), computer techniques and logical thinking all at the same time. Those skills may not increase a school's scores in a school's Comprehensive Assessment tests (called FCAT in Florida; mandated by the Federal "No Child Left Behind" program), but they will certainly advance a student's ability to think and succeed.
Polish it up a bit, do a spell check on it, and set out some guidelines, and I think you may have a hit on your hands. I'm envious.
Don