You should start to decide what area you would like to research, where you would like to go and what supervisors. Check university websites to check their research areas. Having done this, PhD projects that will be available to you next year will be advertised from around december. By all means enquire to departments about possible placements, but you will notice that projects for a september/october 2006 start will be widely available early next year. Hope this helps, best of luck.