Welcome to Flyertalk Keduardop! ^

As others stated, when you get to the airport for check in, you will have access to a seperate first class check in lane. If you are checking luggage, it will get "priority" tags (which may or may not mean much). At PHL, there is a premier security lane - it is usually to the left of the main security line - you enter from the center and then turn left instead of right.

You will be able to use the United Club at all of the airports during your flights. The clubs have free wifi, "light snacks" and free low end booze (you have to pay for the better stuff). The clubs are a nice comfortable place to wait for your flight however. The United Club at PHL is in the connector hallway between the D and C terminals (don't take the moving walkway).

You will have priority (zone 1) boarding. On the plane, the first class seats on your plane have a bit more leg room and are wider, but the big advantage is the separation between seats, giving you more shoulder room.

Of course you will have free booze on board (better quality than in the lounge) and some type of meal. The food isn't exactly gourmet, but most choices are edible. If you are a really picky eater, you could grab something to bring on the plane just to be safe.

You can see a discussion thread about first class meals at this link:
http://www.flyertalk.com/forum/unite...ess-class.html

The service and overall experience is far from the luxury that it once was, but is still much better than coach. If this is your first time in First Class, I'm sure you will enjoy the experience. Be sure to write back and tell us your impressions!