If TimeSlice Lite is not enough, be sure to look at our commercial product TimeSlice.  The figure below is a sample TimeSlice window.
 












TimeSlice has a lot of features that TimeSlice Lite does not.  What does TimeSlice have that TimeSlice Lite does not?  Here's a partial list:

o Client or Job Number column.
o Stop Date column.
o More Preferences so you can customize TimeSlice just as you want it.
o Client/Project/Category list is specific to each file.  Make a change to a
     Client, Project, Category or hourly rate, and it affects only the file you're
     working on.
o Assign the hourly rate to either the Client, Project, or Category.
o Assign color to either the Client, Project, or Category.
o In-line text editing (so you don't have to use the Edit Time window).
o Pop-up menu for selecting a Client/Project/Category.
o Auto-Link other applications to TimeSlice documents.
o Sort time records same way as with the Finder (click on the column name).
o Assign colors to time records.
o Mark Special has additional features.  Mark by Date, Category, Client,
     Project, or Color.
o Set Budget has additional features such as show budget spent or budget
     remaining.
o Export has additional features.
o Import time values.
o Password protection.
o Horizontal scroll bar.
o Print has additional features such as specifying the font and font size,
     grid, column names, and a Print Preview!
o Time Display now can apply to both Elapsed time and Paused time.
o And much more...

Download a demo from http://www.mauisoftware.com.