If you need to get a rough idea on how much XP a party will get from an average encounter for a certain level, consider the Encounter Calculator v3.5.
http://www.geocities.com/edymnionii/EPLvsEL.html
It's a great way to figure out how many encounters a party might need. Remember to divide by 10 (assuming your experience slider for the module is set to 10%).
Credits: Tiera Starr, John Dells, arcady, Maladaar.
Thanks to dirtywick for pointing this out.