Also, having worked on pretty much the exact same product for the French market, one thing I remember people liked was help sections. By that, I mean big long blobs of text that explain the law in detail. On each form page you could display the relevant explainations, and then compile that into a searchable index, and even use that on dedicated pages for SEO purposes.
Oh and maybe you wanna say 'the easy way [to do your taxes]', rather than 'an easy way'.