Can I install VS on two machines with one license?

As per this pdf (Page 1)

A single license for the Software may not be shared or used concurrently by multiple end users.

It looks to me that it can be installed on multiple machines as long as it is not used concurrently by multiple end users.

Also, reviewing this pdf (Page 9) I see

Visual Studio 2010 Client Edition-Only Licensing
Visual Studio 2010 products can be purchased without an MSDN subscription in certain channels. (See the How to Buy section of this paper for more details).The user can install and use the Visual Studio client software on as many devices as they like. However, the products are licensed on a per-user basis—that is, only the licensed user can use the software.

Yes you can, according to this thread on Visual Studio Developer Center/Visual Studio Forums. (And this comes from the Microsoft licensing specialists)