This nifty script by Evgen Zaitsev lets you quickly switch between your current perspective view to side view, and back.
My first Blender Script ( Add-on ). I decided to make something useful, I am using same script in Maya ( I would say same idea ). This add-on toggles Camera from PERSP view to SIDE view and back ( depends of camera vector ). You just need press Alt + Q hotkey. In case if you are already using this hotkey, you will need to specify something else in preferences ( you just need to assign operator view3d.toggle_views_op to any hotkey).