What is this about American English? I'm British and have actually seen the movie a few times (but more about that in a sec) - but there are no American accents in the film. If I understand the other messages people seem to be suggesting that there are Americans trying British accents? As a Brit I would argue with that - I can't spot any out of place or struggling accents. The only thing I would argue is that Will's accent is a lot stronger than that when you hear him speak.
With regards to the actual film, I think it has good intentions but falls short. I first caught it on TV when I was just flicking through the channels for something to watch. I have to admit, the first thing that caught my attention was the impersonations- you have to just laugh when you see the Queen/Duke of Edinburgh/Queen Mum.
No-one in this film is brilliant, but I think most of that could be put down to the awful script. (Abso-bloody-lutely - Ron Weasley anyone?) The direction is pretty shoddy, and it is a serious plot told in an almost jokey style.
And there is no resolution to the story either - is this supposed to be a film about the struggle between Wills and Charles - if so there seems to be no attempt to show them make bonds - they just suddenly do! I say - remake it - but carry the film on - go beyond 2005 - go forward 20 years (probably 40 more likely with the Windsor's lifespans) - show the coronation! Create some bizarre twist in which we see the passing of the two other monarchs and Wills becomes King of the Galaxy!