Marketing my niche web application

I'm a web developer by trade but I work for a graphic design agency.

I've written a subscription service (I own the code) that allows design studios to track jobs, allocate them to staff and track the time and costs associated. Unlike services like Basecamp it is tailored to design studios.

My problem is that i'm finding it difficult to market. I collected contact e-mail addresses for around 20 local design agencies and e-mailed them all asking kindly for feedback. I was hoping at least one would like the tool and decide to upgrade to a paid package. No responses.

I've tried Google adwords but it seems there is limited traffic available in the sort of niche area my application operates. I am not a designer so participating in design oriented forums is quite difficult.

Can anybody offer any tips or tricks for getting my service out there and known?

Thanks,
Jim

My two cents...

37signals started as a web-front design studio only. After building relations with clients they developed Basecamp to be able to manage those clients. The clients liked the interface they built to manage projects, and were more interested in Basecamp than anything else.

I suggest you build relations face-to-face with many clients and see what their needs are.

Go to a tech conference and you will very clearly see what the current needs are.

I would lurk away from Google ads or ads in general. I hope this helps. Id say ads are good if you are selling a product people already know. With no brand you have to build relations first, specially in a very saturated market such as project management software. Go to your local web design studios, know on their doors and present this to them face-to-face.