I'm in a bit of a quandary. I managed to sell an urban fantasy trilogy myself to a large publisher here in Australia. However, after the stress of that, and following various head-thumpings from author friends, I've decided I want an agent to work with in the future.
My question is - do I need to wait until I've got the next project to a suitable level before approaching agents to represent it, or could I get one based on what I've already sold and a proposal for the follow-up? Note that the publisher has world rights both print and electronic, so all I've got of this trilogy for an agent to look after is things like film rights.
I'd rather get an agent sooner rather than later, so I can just keep plowing ahead with developing my career and not having a major break between publications because I need to finish the project to get an agent.
First of all, congratulations - it's a big deal to get a one-book contract, let alone a trilogy!
Now, to your question. It's a tricky time to get an agent, but you've already identified why. There's not much for them to do on your existing contract, so there's no way for them to earn commission and, to be blunt, an agency is a business and we can't afford to work for nothing. Also, again to be blunt, there's unlikely to be a film option because 'fantasy' translates to 'big budget' - when was the last time you saw a big-budget Australian film that wasn't made by Baz Luhrmann? It would need to be optioned in the US and that means you need an agent who has US film contacts. And even if they had those contacts, they're unlikely to take it on just for film because film usually takes a long, long, long time to pull off.
So, yes, it's a bit of a quandary. You can starting talking to agents about your next project - you send an email or call and say you've got the contract and your next project won't be written for a while, but would they like to talk. You may find someone who loves fantasy and is happy to talk to you now. What's more likely to happen is that they'll ask you to keep in touch until you have a little bit of your next manuscript ready to show and then make a decision based on that.
However, there's another way. If what you want is for an agent to come in on the existing contract - to ask questions about foreign rights, to do film, for you to generally chitchat with - then you may be able to come to an arrangement. It's not common but I've heard of it being done - you may ask the agent if, in exchange for commission on the rest of the advance payments on your existing contract, they will take you on for any work relating to that contract (and that can include editorial feedback on the rest of the trilogy). The agent should not - cannot - take a fee for this, it has to be on commission. But the option is there and you can ask about it.