Hi Becky- I dont know what field you are in, but it seems to be that most PhD's in social sciences (or a lot them) can be applied for most of the year, but it might be an idea to get an application in as soon as you can. Funding is the big problem I think- there are usually strict deadlines for this, and it depends on who you apply to for funding (external funding bodies have their own deadlines, and universities have their own deadlines for handing in apps to external funding bodies, and different universities have different deadlines for their own funding) presuming you need funding. If you have an idea of where you want to study and what, it might be an idea to contact them and ask about it.