Any good car log apps out there?

I have a 2004 prius and my MFD recently went out....so sad. So I decided to go looking for a good MPG app for my iphone since I could no longer use the car's builtin feature.

I really don't like the native apps that just keep the data confined to the phone and I find emailing my data around and having to do things in a spreadsheet to be painful. I recently came across cargly.com which is an online app for doing lots of car stuff, but it doesn't have a native iphone app yet (it does have a pretty good web based iphone look, though). I guess I am too picky. I want my data all online, but the app to be native, so it's snappy and responsive. The cargly guys did reply to an email I sent and they tell me they're working on an iphone app, but I am not very patient.

So, I am wondering what other solutions you folks have found.

As for my MFD, anyone ever replaced one? How hard is it?

 

Have you never used something like RunKeeper on the iPhone? It lets you track your jogging/running and when you're done you can view all your data on their website. That is what I'm looking for only for my car. I don't think cargly.com is the perfect car log, but I prefer the model of doing data entry with my phone but viewing charts and doing any analysis somewhere else like my laptop or wherever. Other features seem more natural with the online model, like with Cargly I can easily share a car with my wife and either of us can easily record fillups or whatever.

BTW, what's up with the way Gas Cubby shows fillups. It puts the MPG on the first fillup instead of the second. Huh? I had to check its math, because it looks like its using the gallons from my first filll up instead of the second fillup. It kinda looks like this (not real data):
second fill up 10 gallons odo=60500
first fill up 9 gallons odo=60000 mpg=50 <-- huh?

That's confusing! It is doing the calculation correctly (500 / 10) but it looks like it's using the 9 gallons since it is on the same line as the 9. I minor thing, I guess, but like I said it made me question the whole accuracy of the app. I haven't done an extensive survey of other apps or anything, but I am pretty confident that putting it on the same row as the second fillup would make more sense.