Is L smarter than N

Surprisingly, no.

In Death Note How to Read 13, it is clearly stated that Near's intelligence level exceeds that of L by at least 10%. Another reason why Near's my fave character :)

http://img39.onemanga.com/mangas/00000026/0000011013.jpg

http://www.onemanga.com/Death_Note/110/09/

~N

Second Answer:

Yes.

Ohba, the writer and creator of Death Note, said that L is the most intelligent character in the entire Death Note series.

Sources: Wikipedia