Well, actually it is easiest if you get them straight in camera. Those who use PhotoPaint and have seen PSP or LightRoom in action can develop Horizon Correction envy. It is actually quite easy to correct horizons in PhotoPaint without scripts or complex calculations.
I have put a tutorial (1.4 MB Video) HERE
I hope it is useful.
My nikon D70s has a raster in the viewfinder. I don't need any software to fix that.
That is great, if you remember to take advantage of it. Many times your eye can fool you and you will think you are straight only to realize you are not.
Shoot it right in the field is my mantra. However, not everyone in this group has the luxury of providing solely their own images. For them, straightening is a necessary evil.
I have an article here on the importance of shooting straight and what it means to the photgrapher and designer: Leaking Megapixels Down the Drain
Rikk Flohr said: That is great, if you remember to take advantage of it. Many times your eye can fool you and you will think you are straight only to realize you are not. Shoot it right in the field is my mantra. However, not everyone in this group has the luxury of providing solely their own images. For them, straightening is a necessary evil. I have an article here on the importance of shooting straight and what it means to the photgrapher and designer: Leaking Megapixels Down the Drain
yes, sometimes I forget to turn on the raster... but it depends the experience to keep horizon straigh. I have around six years in photography and a lot of time I was working with Nikon F60 (on film). That camera wasn't has raster.
Whatever, for all that are only using pictures, not taken, any software / technique idea is welcome...