[R] factorial experiments and repeated measures

[eesteves@ualg.pt]

Dear All,
I'm new to the list and relatively new to R (but not so to S-Plus) and I´ve 
been asked to help study some experimental data.

In a factorial experiment (5 factors at 2 levels) the response-variable was 
measured at various times (0, 2, 5, 7, ..., 30 days after start). There's just 
one run for each factor combination! I intend to use the nlme library of 
Pinheiro and Bates in a longitudinal data situation but I have some 
difficulties with the "statistical scenario" of it all! 

The factors are not nested and the number of repeated measures is unbalanced 
(in some cases they were abandoned for some reason before the end of the 
experiment). The main objectives are to identify the factor(s) that influence 
the response and to model it.

How should I dissecate this? If in need of more info, just ask!

Thanks. Best regards, Eduardo Esteves