find last day of month

["Andrus Moor" <eetasoft@xxxxxxxxx>]

I have a table containing month column in format mm.yyyy

create table months ( tmkuu c(7));
insert into months values ('01.2005');
insert into months values ('02.2005');

How to create select statement which converts this column to date type 
containing last day of month like

'2005-01-31'
'2005-02-28'

Andrus.