Hi Twiga. I really don't want to be negative here, but the system is totally different in England so you probably need to know this We are now in Sydney but my 3 kids were all born in Brighton and we lived there for 12 years. If you go onto the Brighton and Hove Council website and look up FIS (Family Information Service) that's probably your best source of info.
Your daughter won't be entitled to early education funding Spring term 2009 (not after the October holiday - I just checked it on the B&H Council website) so there is no option to start a funded nursery place in September. My daughter turned 3 in February 2006 and she received "nursery funding" at the private nursery she was in from April 2006; she then got a place at a nursery class attached to a school the following September (the year before she would have started school). My older November born son was offered a nursery place at Tarnerland starting the September before he turned 4.
There are two very popular State nurseries in Brighton - Tarnerland and Royal Spa (both in the Queens Park area near the hospital) but you basically put your kids name down on their second birthday and then they draw from the waiting list. They have a morning and an afternoon class (2 1/2 hours per session) of around 20 kids each. I'm not even sure they would put your name on the waiting list if you're not living in the area, and it's probably too late anyway, but it might be worth checking out. There aren't that many schools in Brighton with an attached nursery class and remember, it is no guarantee of a reception place in the same school, so if you don't live in the school catchment you might want to think if you want to send your child to the nursery class of a school that you won't get her into later.
There are a LOT of private nurseries in Brighton, but the good ones all have waiting lists. Have you any idea where you are going to live? that's probably your best starting point. The other option would be playgroups.
If your OH is working at the RSCH Queen's Park/Hanover is a fantastic place to live with a young child. Queen's Park is the nicest park in Brighton (in my opinion of course!) with wonderful homemade caks and you're not that far from the beach. There are LOTS of young families around, good family friendly pubs and until your family outgrows the (mainly) smaller houses around there it's a brilliant place to be. We moved around there when DS1 was 2 and I thought that I would never leave Brighton (by the time we had 3 kids that changed a bit!!!).
There's a great Brighton mumsnet crew - keep an eye out for their meetups and good luck.