In my opinion, you have way too few experience to be a good project manager at the moment, but you can evolve, learn from mistakes and eventually become one.
The first thing you should do is setup a software to manage your work items. TRAC is a configurable ticket system for example. Collect all work items/features the app should have you currently know of and gather them there. This will be a rough spec for your project. You can also use it as a bug database later on. It also features some statistics and there're lots of plugins available, you can use it to measure and analyse the progress of the project.
Then, use it and create a road map for your project, which should include all big milestones you want to reach. Each point should be the completion of a subsystem or essential component or feature. It'll be damn hard for you to estimate the amount of time necessary with your level of experience, but you'll eventually learn to estimate quite correctly.
Then, start planning the software technically in small steps, e.g. componentwise. Use UML or at least create a rough outline on how you are going to achieve your goals technically. Define the technologies you will use and definetely plan your technical infrastructure/architecture. How will you use data access? Where do you need interfaces? What is likely to change? Where do you need interchangeable parts? How will you glue everything together? How are files being organized?
Did I mention you should create coding conventions already? They should include information about formatting, naming of methods/classes/components/ui elements, do's and don'ts, hotkeys, ui design guidelines etc. Your team should adhere to them.
Then, start assigning your team members work items. Show them how to implement things so they fit within the architecture. Give each team member the tasks that best suit him/her. If someone is good in design, let him do the views. If someone is good in algorithms assign him to the more complex businesslogical stuff.
Then start implementing. Always measure your teams success and adjust your project plan/roadmap if necessary. Don't forget to test closed tickets. Only accept a close if everything works. It's your job and responsibility as a project manager, especially if you haven't got any QA guys!
Talk to your team members every day for five minutes. Let them report their progress every day in a short form. This will enable you to spot deficits in progress early and help out or assign other people to critical parts of the system, if someone needs help.
That's it for the junior management part, I'd say. You also should set up a build system like hudson or cruisecontrol and include unit tests for your software, so you can produce a build in one step. Of course you also need source control. Take subversion/git or mercurial, they seem to be the hot ones out there.
This should get you started.