I work at an employment agency- We have employees for at least 90 days (sometimes more than 90 but never less than). I am trying to create a formula or a rule that will display either red or an icon that will let me know (by glancing) which employee is past their 90 days or if it is getting close to their 90 days.

For example:
Employee Start Date
John Doe 8/1/2012
Jane Doe 4/1/2012
Johnny Doe 2/1/2012
Bill Doe 7/1/2012
Jo Doe 5/10/2012

Please let me know if I can explain it better or if I need to add more information...

Thank you for your help!