Although I have to admit I'm not always sure exactly where the loop is, I can say that I enjoy being kept in it. On the Mac, my favorite program for doing so is Growl ( Macworld rated 3.5 out of 5 mice ), the free open-source framework that lets you customize notifications for supported applications, popping up a window to let you know a download is finished or a lengthy file conversion is finally done. On the whole, it's more flexible and elegant than just a straight up dialog box.
But what about when you're on the go with your iPhone? Maybe you still want to know whether some task on your home Mac is done. For that, there's Zac West's new Prowl application for the iPhone. Prowl is a Growl client that can tap into your Mac's Growl notifications and display them as push notifications on your iPhone--don't worry: your notifications will still be displayed on your Mac, too. Prowl can store notifications for up to 30 days, and when you open the app it displays them in a scrollable list, ordered by the application that sent them. There's also the option to have alert sounds played on your phone when you receive notifications.
The app requires that you have Growl and the Prowl plugin installed on your Mac and a free account on Prowl's server. (That server is used to shuttle data from your Mac to your iPhone.) Prowl's got a few options in addition: for example, you can tell it only to send notifications to your iPhone when they're at least a certain level of priority (high or emergency, for example) or when your Mac's been idle for a certain amount of time.
Prowl for the iPhone is $3 and requires an iPhone or iPod touch running iPhone OS 3.0 or later.
