You can also check your credit report. The day of the inquiry is usually the day of approval/denial.

With Citi it's almost always the same day (they usually pull the report "while you wait" after you submit the app).
With Chase it's generally the following day (not sure why - just takes them time to get info from one system to another I guess).
With Juniper it always seems to be pulled "while you wait," but if it goes into manual review, you can check http://www.applicationstatus.com and they'll tell you the date of your approval.