I hear ya, Wolvie.
I hand out a "Usage Glossary" to my students that I go over in detail. The ACT & SAT are coming up soon, so it helps with that. But it is also just Good Writing. The list has (up above) [i]then/ than, alright/ all right, affect/ effect, its/ it's[/i], among others.
In fact, I just did this last week, so it's on my mind. Above blunder excepted !(argh)
