Liverpool. It opened on Saturday and will run until Wednesday. Further details are available here. The conference directory - which details the sessions and fringe meetings can be accessed here.
There are two Labour Party Conferences next week. The first conference will be held on Saturday, for the purpose of announcing the result of the election of the new Leader of the Labour Party. (you can sign up to get the results texted to you here. The Annual Conference begins on Sunday. Details of fringe events are available here. The Conference is being held in Manchester.
The final conference (of the major UK parties - smaller & regional parties also have their conferences around this time) will be that of the Conservative Party in Birmingham on October 3rd to 6th. Their fringe programme can be accessed here.