Yes I Can!

Steps to use your Android Phone as a PC/Laptop Mouse without a Bluetooth connection
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First of all search and install Padroid from the Android Marketplace on your Android mobile.
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After installation just run the app and you will get a screen like this:

Now open up a web browser on your Laptop/PC and type in the URL as shown on your mobile screen. You will get a web-page as this one:

* Next all you have to do is click that blue power button on the web-page.
* That’s it. Voila ! You can down tap and touch the screen of your Android mobile and control the cursor on your Laptop/PC screen. Just move your finger on the mobile screen to control the cursor movement. Single tap on the mobile screen does the job of left-click on your computer. And tapping with two fingers does the magic of right-click on your computer. That’s it.

Note: Do not panic when the mobile screen goes all black. It is normal when Padroid runs and this is how it works. The black mobile screen is the touchpad for your Laptop/PC.
I have tested this app on HTC Wildfire running Android 2.1 (Eclair). Also, no rooting is required for this app.

As mentioned on the web-page, the app is in demo version only and provides basic mouse functionality for now. But developers have planned to release bunch of other features when the official app rolls out.