The Xpenser iPhone interface is now live, available by visiting http://xpenser.com/ via your iPhone.

We wanted to express our sincere thanks to all of the testers; the quality of your feedback was unbelievable. We’ve incorporated the first round of feedback into the interface and will be rolling out the rest over the next few weeks and months. We still want to hear from you, so leave comments here or email us at feedback@xpenser.com . Don’t be shy about direct and honest feedback; we’re just as happy to hear about what could be improved as “it looks great”.

To make it easier to get to Xpenser, once you visit http://xpenser.com/ with your iPhone hit the “+” icon at the bottom of the screen and select “Add to Home Screen”. This will put the Xpenser icon on your iPhone home screen and allow you to enter your expenses with a single click.

The iPhone interface for Xpenser is starting to look pretty good. If you’re an Xpenser user with an iPhone and want to test (or to get a sneak peak) let us know at feedback@xpenser.com and we’ll send you instructions.

We like a lot of what 37 Signals have to say. If you’re in the software or design business give their writings a good look.

One of their recurring themes is keeping things simple and knowing when to say no to features. We were discussing this recently when an interesting topic came up: what about the existing features?

We’ve done some analysis and found that the majority of our users aren’t aware of the majority of features Xpenser offers. Which is odd in some ways, given the relatively few features we’ve exposed.

There’s a very good argument to be made for putting time and effort into making the existing features more obvious, more accessible, and more usable, instead of introducing new features. We’ve attempted to keep the features in the product flexible so you can use them in a variety of ways; in fact we’re continually surprised by the innovative ways you use and combine features to solve problems. This is the mark of a good feature. We’d create more value for more people by making these building blocks better known.

We’re not going to stop introducing new features; we have a fairly clear set of things we want to implement to make Xpenser more useful. However, we will be going back and looking at how to make the existing features and capabilities more discoverable and easier to use. And as always, we’d love to hear your take on it. Drop us a comment below or let us know at feedback@xpenser.com.