I need help choosing an online project management application

So this morning I got an email from a press release customer. Actually it was a private message from the forum where she initially found me.

She said that she had emailed me some project specs, but I hadn’t received them. I emailed her a clipping report detailing where her press release had been syndicated, also noting that I hadn’t received the second set of specs. Somehow it seems those emails aren’t reaching their intended destinations.

While email is free, it may not be the most efficient or responsible way to collaborate with my clients.

So I’m putting out a request to you, my readers… do you have any recommendations for an online project management application?

I don’t need a lot of bells and whistles. Just something that would allow my clients and I to communicate in a shared space. Plus I need space to upload the press releases so that each client has their own file storage. A free trial would be nice, but it’s not a necessity.

Any help you can offer would be greatly appreciated! Please leave your recommendations in the comment section.