Praveen,
There are a couple of ways to achieve the result of a drop-bown box. To add a simple input box (Drop-Down, Free-form Text, etc.) to an individual App, read this blog: http://www.jackbe.com/enterprise-mashup/blog/app-tips-blog-getting-personal-inputs. Alternately, to add an input form to a Dashboard of Apps, check out http://www.jackbe.com/prestodocs/v3.0/mashboard/addForm.html.
I hope this helps!
Chris


Praveen.N.Pagi.