BillShrink, a website that offers free personalized analysis of cellphone, credit card and gas costs, has lined the phones up in an easy-to-read chart (click image to enlarge). It compares …

• Apple’s (AAPL) new iPhone 3G S, which goes on sale next Friday
• Palm (PALM) Pre, which went on sale last Saturday
• HTC’s G1, the first cellphone running on Google’s (GOOG) Android platform

BillShrink’s bottom line properly draws attention to the total cost of ownership over the life of a 2 year contract.

It shows the iPhone on AT&T (T) — at $3,799 for unlimited voice and messaging — to be most expensive by far: 20% more than the G1 on T-Mobile (DT) and 46% more than the Pre on Sprint (S).

[NOTE: An earlier version of the chart did not include the cost of the iPhone and Pre in their totals.]

But the chart also makes it clear that in several respects you get what you pay for. For example, the new (entry-level) iPhone comes with twice the Pre’s memory capacity and 16 times the G1’s (although the G1’s memory can be expanded to at least 16GB).

And the chart actually underplays the vast advantage the Apple’s U.S. App Store (with nearly 50,000 programs) has over Android’s Marketplace (nearly 5,000) Palm’s App Catalog (18).

As for the total cost of ownership, your mileage may vary. If you don’t need unlimited voice and text messaging, the iPhone and the Pre can each be had for $69 per month, for a total cost of $1,878.76 over two years (taxes not included).

F0r more smartphone comparison tools, check out BillShrink.com.