Jo has never directly *said* that James *was infact* in Gryffindor (and on the subject, minor spoiler, um, James a Seeker anyone?)

[maneelyfh]

No: HPFGUIDX 65972

--- In HPforGrownups at yahoogroups.com, "goingoutsleepwalking" 
<goingoutsleepwalking at x> wrote:
> >  - Yeah, but we got canonical confirmation in OoP:
> > (Can't find the page at the moment cos the book's too big - 
someone  can
> > back me up, please?) "Harry was forcibly reminded of another
> > Grffindor Quidditch player who had sat under that very tree,
> > ruffling his hair" - the first GQ player being Ron, the
> > "other"  James.
> > Kirstini
> 
> Still not saying that he wasn't, but the books are written very 
much from
> Harry's perspective and *he* still *assumes* that his father was in
> Gryffindor. > 
> goingoutsleepwalking

Further Proof he was:
In the first book SS, Hermione points out to Harry that his fathers 
name is on a Qudditch cup that Griffyndor won years ago.
fhm