I have a good idea on mobile applications but i dont know much about it. I dont even have a computer. I need an advise on where to start from. Thanks.

You need to get in touch with a developer or learn how to develop the app yourself (could take you a year). If you decide to sort the app with a developer, you MUST get them to sign a non-disclosure agreement (or be done in like the originators of the facebook idea). There are many examples of non-disclosure agreements on the web, here's a google search; http://www.google.com/search?hl=en&q=non-disclosure+agreement&meta=&rlz=1I7ADSA_en

Before you start, there are key questions you need to answer;

[list]
[li]What platform is your target market on (android, windows, symbian etc)?[/li]
[li]Would your app be suitable as a webservice or would it need to be installed etc (what is the architecture)?[/li]
[li]What programming technology should it be written in (flash, silverlight, java, c# etc - keys into first point in many ways)?[/li]
[/list]

No man is an island and gifts are shared differently between every one by the Good Lord. If you can generate good ideas then you must find someone who can generate good programs. Maybe you should sell the idea as a patent.
That way you will profit from it.