I was just wondering if it was possible to have smooth lines in photoshop the same way it is in flash where when you draw a figure it will automatically change the lines you made into smoothened shapes, I would like to know if this is possible with photoshop and how you would do so. Thank you.
Lazy Nezumi is a Windows application you can buy for this functionality.
Here is a demo video: Smooth lines with Lazy Nezumi
It works by smoothing your mouse input points, so it works with any drawing program (not only Photoshop). If you're familiar with real-time smoothing, you'll recognize the characteristic "lag" behind the mouse cursor:
First of all, you need to understand that Photoshop is a raster based tool, so you can't get the same smoothness you get in vector based tools like illustrator or flash. But you can create a smart object to achieve that smoothness in your vector shape. The advantage of using smart objects is that you can resize them (make them bigger, they may lose some quality but are still manageable).
The best way is to draw vector shapes in illustrator and then bring them to Photoshop so you will get perfect smooth lines and curves.