I spent about 30 mins trying to write an app last year... Couldn't get the cookies right, but it shouldn't be too hard. There are some cool Java API's that handle cookies and http requests.
I doubt that any of the ISP's will have API calls to get hold of the stats.
I reckon running that PHP webserver that uses cURL to get hold of those statistics would be the easiest. cURL does the cookie management for you, and since you're also running it from a webserver, you can display the original content easily too.
Handling cookies in C# or Java isn't difficult either.
Antibody Software also mode an application called SASA. I'm not sure if they support all the latest/new ISP's stats pages though since it doesn't look like the application was modified since 2007.