generalized linear mixed models: large differences when using glmmPQL or lmer with laplace approximation

First of all, thanks a lot for the info.

I know the differences seem small, but most ecological journals still
let their opinion about ecological relevance of predictors depend
completely on p-values... So I think I'll stick to lmer because of the
Laplace approximation.

Well, Laplace should be better anyway.  (If the difference were in
the other direction -- non-significant with Laplace and significant with
glmmPQL -- I would still tell you to use Laplace.)

  To speak to Greg Snow's comment ("don't worry about p-values, just
look at predictions") -- this is really tough.  I still don't know
what to do about the compromise between how statistics should be done
and how journal editors seem to insist it should be done ...

  cheers
   Ben