Zdobyslaw Kacprzak
Zdobyslaw Kacprzak voted up Cookie Roma's answer
My new neighbors parks in street and makes it almost impossible for me to get in my driveway without hitting their car, esp. when there is snow.. Should I go to their house and ask them nicely or write them a letter. I don't have their phone number?

I think it is always best to go over in person. Just NICELY explain that you'd really appreciate it if they could park the car just a bit up from where it is. 

Zdobyslaw Kacprzak
Zdobyslaw Kacprzak voted up Call me Z's answer
My new neighbors parks in street and makes it almost impossible for me to get in my driveway without hitting their car, esp. when there is snow.. Should I go to their house and ask them nicely or write them a letter. I don't have their phone number?

If these are your neighbors, you will be well-served to build a civil, if not outright friendly relationship with them. Go over and make nice, explain the situation politely, you'll likely get a more positive response than just sticking a note on their door. That could be interpreted as disrespectful or cowardly.