Activating a dynamic sidebar with some widgets included in it.??

Hi ,
while creating a theme i have created some sidebars in functions.php.
Now what i want is , when someone uses my theme the sidebars will be created and some widgets too. But how will i inckude specific widgets in specific sidebars.

e.g:
i have created a sidebar(say x) in function.php also 2 widgets(w1,w2).
i want those two widgets to appear in the sidebar x when someone activates the theme.Here the user does not have to drag and drop the widget in the sidebar.the widgets should automatically get added to the sidebar.

If any1 can point out some functions or anything will be highly appreciated.

Regards