There are hundreds of pieces of web and desktop software available that could help you. Most of them will offer free trails so I recommend you try a few and see what works best for you.
Here are a few I use:
Podio.com: this has an iOS app that goes alongside the website, you can have many projects, invite clients to post on message walls, set up projects and goals and customise pretty much everything about it. Layout finance plans, set task lists, assign tasks to collaborators. It's very full featured.
Trello.com: This is similar to podio, but simpler and easier to use. It's basically like a pin board with cards on it, but you can attach images, make todo lists, and rearrange the cards and move them into categories. Good for project management but not so good for clients
HarvestApp.com: This has some really handy time keeping software, all my client information, I can track expenses and projects, and it will generate and send my invoices for me based on the hours I've tracked, per project, and send them to the right client.
Those 3 are probably my favourite, they all come with really good iOS apps (probably android too), but like I said, you should try a few and see what works for you.
From what you've described, Podio might suit you well