LMP1 is still allowed in the ILMC/WEC, the top tier of sportscars, and therefore in the 24 Hours of Le Mans race. That is absolutely certain and that's where the likes of Jaguar, Porsche and McLaren will fight one another come 2014.
The Le Mans Series (LMS) is a Europe-only series one tier down from the ILMC/WEC. It doesn't count the 24 Hours among its points-scoring rounds, though people who do well in it get automatic entry into the following year's 24 Hours of Le Mans race (unless they're in the Formula Le Mans class, due to a lack of equivalent category in that race). It won't be sharing any dates with the ILMC/WEC next year (this year it shares three rounds - Spa, Imola and Silverstone) because events where they shared have been very oversubscribed and the LMS didn't think it was fair on the teams that got refused. There are very few LMP1s which only do LMS - one Rebellion (the other is in the ILMC) and the ORECA Peugeot are the only ones I can think of.
I think the ALMS (the LMS' American equivalent) will also allow LMP1s, giving teams in that class not ready for a worldwide calender somewhere to go. However, this is still under debate, among a great many other things. It will share at least one round with the ILMC/WEC next year, possibly two if the idea of having a race in South America doesn't work out.
There's a third regional series, the Asian Le Mans Series, but that has bigger problems - such as getting a calender featuring more than one race.