I would highly doubt that 2005/10 is not compatible with 2010.

Regardless, if you have already retrieved the data in the application and all you have to do is to display the data in a report, there isn't too much to do.

The general steps would be to create report viewer, and a report. (this should be easy to find on the web).

for building the report, if your app already has the data, just set your dataset to the datasource of the report. As for designing the report using the data from the app, stop your app after the dataset is complet and have the dataset write itself out to xml(dataset.writexml(file name, withSchema). in the report set the data connector to ado.net, and point it at the file you just wrote out. Now just design the report...

I realize its a brief overview, but it should be enough to get started/pointed in the right direction and what you need to look for.