Motorola is a member of the Open Handset Alliance which, according to their website, is a "group of more than 30 technology and mobile companies who have come together to accelerate innovation in mobile and offer consumers a richer, less expensive, and better mobile experience." Keeping the description in mind, it's no surprise that the company is investing more in its Android developer team. A post on popular technology blog TechCrunch states that Motorola presently has approximately 50 people on the project, however they are currently working to expand it to as many as 350 people.
Nokia and Verizon representatives were seen at a recent Android conference, although neither of the two are members of the Open Handset Alliance.
Source: CNET and Open Handset Alliance