Hey, Karen -
Nice to see you back on the forums!
I'm not actually sure about the copyright issue - I'm sure there is one, and I know that some people will police their copyright a lot more vigorously than others.
My two rules of thumb if I'm quoting people in books or tips:
1. If I can (i.e. if they're alive!) I will seek permission directly
2. Always attribute as accurately as you can and spell their name right!
Can you post any of your designs here on the forums?