UA 1P (Premier Executive) means you're gold and can use the lounge.

This is a handy site to know which lounges you can use:
http://www.united.com/page/article/0,1360,3113,00.html

I also recommend checking out the rules on the *A page in case you meet someone and want to bring a guest (ps, you can!):
http://www.staralliance.com/en/trave...s/lounges.html