If you’re let handed then using the right centric mouse of your pc might be a bit uncomfortable. Instead of buying a left handed mouse you can simply switch the mouse buttons to get a left handed mouse. Here are the left handed mouse pc settings in windows.
Settings to Make Mouse Left Handed in Windows
Step 1 : Go to Start. Type in Mouse. You can also access Mouse settings from Control Panel.
Step 2 : On the Mouse properties window click "Switch primary and secondary buttons" box to make the mouse left-handed. Basically now the now the buttons are interchanged. (In Windows 7 simply select Left Handed and click ok.)
Step 3 : Finish by clicking Apply and Ok with the new mouse settings.
Changing to Left Handed Mouse Cursor (Optional)
Go to this Link (MSDN) to download a list of Mouse Pointers for Left Handed Look. Follow the documentation to install the left handed cursors for a better looking left handed friendly user interface in windows. You can also download all of them directly from this link (I collected them in one place).
Basically go to Mouse Properties > Pointers > Browse to select the cursors downloaded.