QuickCal Mobile is an app that lets you quickly create new events for your calendar using plain language typed into a text field.
Mac users may know QuickCal from the free Dashboard widget of the same name, and the interface shares some similarities: you create events in the same way, by typing into an always-on text field. QuickCal will automatically recognize most parameters--for example, "Go to gym tomorrow 11-noon," "Yard work next Saturday at Dad's house," or "Team meeting next Friday for two hours starting at 3." As you type, the app will show you a live update of the event's description, location, and start and end time and date, and as soon as you press "Done," the event is entered into both iCal and QuickCal (which has an attractive, scrolling quick-reference calendar of its own).
QuickCal isn't flawless (you can't, for example, say "a week from today," because "from" usually precedes a start time), but overall the app does an excellent job of interpreting what you type, with nice touches like flexibility as to how you enter time (accepting variations such as 4, 4pm, 4:00, 1600, and so on). A bar at the top of the interface shows which calendar your event will be placed in, and you can tap the bar to toggle between calendars. The app also has settings to change calendar appearance and the default alarm for an event. A "Smart Reminder" system automatically sets earlier default alarms for events that are further in the future--such as reminding you days ahead of time for events that are weeks away, or weeks ahead of time for events that are months away.
Thankfully, QuickCal Mobile's interface has gotten much better in recent updates--early versions were not pretty--but it still might not jibe perfectly with your work flow (for example, the longest default alarm available is 1 hour before, which means you'll need to manually add any longer alarm). That said, QuickCal Mobile is very easy to use--and as it lets you bypass iCal's multiple menus, fields, and buttons, QuickCal Mobile is typically a much faster way than iCal to add new events to your calendar.