For e-mail communication, you can use info at ulpi dot org. 

For snail mail, our address is given below.

NXP Semiconductors
620A Lorong 1, Toa Payoh, TP3, Level 3,
Singapore (319762)
Attn: Shaun Reemeyer/Yeo Hock Meng

We will try to come back to you as soon as possible.