Is there going to be a second professor Layton movie?

Yes there is another game: see below:

Professor Layton and the last time travel has now been renamed Professor Layton and the Unwound Future.

Professor Layton 3, Professor Layton and the Unwound Future, has a confirmed release date of 20 September 2010 for North America. Expect a similar release date for Europe

The latest UK date for the release of Professor Layton and the Unwound Future is 26th/27th/or 28th of October 2010, issued by Amazon.