How to straighten horizion

[pjs2]

Hi,
I need help to work out how to straighten my horizions using ps 6 .I was able to do it before but for the life of me cannot remember how. It had to do with the measure tool but that's about all I remember.

----------------------------------------------------------------------------------------Need help bad
peter

[ricktas]

ruler tool. Draw a line along the horizon, then go image > adjustment > rotate : Select Arbitrary and the box with the degree of rotation should be pre-filled, (based on your ruler line), just click OK. Then Crop

[pjs2]

Thank you so much. I knew it was fairly simple but the brain just wouldn't kick in.