Today, Ars Technica posted a very handy guide for keeping up with the new, popular and discounted applications in the iTunes App Store. Here are some great pages and feeds you might want to follow to keep you on top of your iPhone App choices:

1. App Shopper New Applications
AppShopper offers a new applications page and RSS feed. These resources track new items as they appear at App Store. If you’re only interested in free apps, this new and free RSS feed is what you’re looking for. The pages and feeds are nicely designed and easy to use.

2. 148 Apps Price Drops
This page provides up-to-date overviews of the latest App Store sales and price drops. The site automatically scrapes the store looking for bargains and adds them to its page. You’ll find several discounted items per day.

3. Medialets Metrics/Medialytics
If you’re more interested in learning how well an application is doing rather than what’s new or discounted, Medialets is the place to turn. It offers a constantly updated ranked list of App Store items. Medialets provides the sales rank, the average rating and the total number of ratings for each app.

4. Pinch Media Updates
If you’re looking for updated apps, Pinch Media has the perfect RSS feed for you. It scans for all apps with recent version changes. Let this feed help you decide when that Application you held off buying really is worth the money after its update.

5. Apple’s App Store Roundup
Discover new, free and top Apps directly from Apple’s site. This interactive browser lets you quickly scan through top items in a number of categories.

Be sure to check out Ars Technica for more info.