For the kindergartens I applied to they don't even start putting out applications until your child is roughly 2-years-old. So, even if you go and ask for an application, they will not accept it until they are ready to take their intake of applications. So, applying early doesn't do you any good. It's more about the interview process rather than the application submission process. For example, my son (born November 2007) started kindergarten in September 2010--he wasn't quite 3-years-old. We had to apply to the school the previous October 2009 and he had an interview with the school in November 2009 when he was not even 2-years-old. The results of the interview determine if your child is accepted--not the submission date of your application. Obviously, your 6-month-old won't even be able to interview for kindergarten for at least another 1-2 years. Just keep your eyes peeled for announcements from schools.
As far as nursery school goes--if you want your child to attend, yes, get an application and get it in. Children can start attending nursery at about 2-years-old. In our village there is only one nursery school and there are only 15 spots in that school. I just turned in the application for my 3-month-old only to find that they have already received 25 applications from children born just between January and May 2011! I ran into this problem before when my son was born--I put in his application with the school when he was a year old and had absolutely no hope of getting him in so he ended up attending a nursery school much further away from our house which was inconvenient but the best thing for him for social purposes.
I am actually a big fan of nursery school as long as it's a good quality one--and there are some really horrible quality nursery schools--I've seen some that made me scared to send my child there. But, my son attended a really great nursery school for about 6 months and loved it. The nursery school he attended had a special section for children with disabilities. My son doesn't have any disabilities but I thought that the integration of those children into the program went a long way to helping children learn tolerance and acceptance of others. It was a really great environment and the teachers were all very experienced and patient. My son loved going there.