Just a simple plasmoid i coded up in 15 min to save me some time.
I built it with KDE 4.1.4 but it should work fine with KDE 4.2.

To use:
1.Just type the search term and press ENTER.
2.The default search option is set to use google and opens the results page in Konqueror.
3.To use Wikipedia,type:
w search term here
4.To use IMDB ,type:
i search term here
5.To use yahoo,type:
y search term here
6.To use Google(the default),type:
g search term here

As you can see all the options are hard coded,so it is not possible to add or remove search engines at the moment.

If u like to improve this , your are free to do so.

Install instructions in source.