p_values for GLMM

Dear R-users,
I was wondering if anybody knows if it's possible to obtain a p value
for the full model of a GLMM with the lme4 package. I was told that I
should check whether the full model including all the predictor
variables is significant before doing stepwise regression or further
analysis, but I can't figure out how to do this. I also wanted to know
if there's a way of obtaining residuals or predicted values for the same
analysis.
Thank you very much.
Cheers,
Cristina.