Can 'date entered' be auto entered in a new task?
 

When posting a new entry in OmniFocus, is there anyplace that the current date of the entry be auto-posted in the task?

Currently I must enter "today" in the "start" field.

I don't think there's an automatic way you can do this, but here's a manual way that will allow you to do this for all of the stuff you entered today in one quick operation.

Go to context mode, group by Added, sort by Added, all actions. This will give you a list of when all of your actions were added, and allow you to easily view just those added today. Now select everything in the Added Today group by clicking on the first one, scrolling down to the end of the group and shift-clicking on the last one. Bring up the inspector with cmd-shift-I and type "today" into the Start Date field and you are done.

Do note, however, that if you use repeating tasks, any newly added tasks (due to repeating) will show up in this list, so you might want to look it over carefully before setting everything to have a start date of Today (you wouldn't want to change the start date on a repeating task if it repeated weekly, for example). You can remove individual tasks from the selection list by cmd-clicking them.