According to this:
http://www.trap17.com/index.php/what-programming-language-google-etc_t34833.html
Google uses a lot of programming languages :)
He is right about their job requirements:
Requirements:
BS degree in computer science or related technical field, MS and PhD degrees preferred.
Experience with UNIX/Linux or Windows environments, distributed systems, machine learning, information retrieval and TCP/IP.
Extensive experience programming in
C, C++, Java and/or Python.
Experience in network programming and/or developing/designing large software systems
Copied from:
http://www.google.com/support/jobs/bin/answer.py?answer=75572