QUOTE(andante @ Jun 20 2009, 01:55 PM)

Thank you all for replying, I know nothing about horn. (I played classical guitar, basson and piano. Daughters play clainet and piano / flute and piano) I'd like to encourage my son with his horn by getting him nice things to play, he enjoys playing, but is apt to lose interest without a bit of encouragement.
Perhaps I should wander off and find a brass forum elsewhere.

Why not look for one of those but hang in here as well? You never know, there might be a sudden influx of horn players!
Here are some ideas for you. I don't know definitely that any of them are still in print as our copies have been around for quite a long time.
New Pieces for Horn (2 volumes, Grades 3-4 and 5-6) published by ABRSM c.1980. Vol.2 has 8 pieces by 5 different composers, and I think all the pieces were new for the books.
Horn music for Beginners (don't take that seriously - Hungarian beginners are different from UK ones, probably mainly thanks to Kodaly, a familiar name in these parts

). Over 20 pieces, a mixture of arrangements of music by composers from earlier times and 20th century Hungarian pieces. Original publisher Editio Musica Budapest, probably available through Boosey & Hawkes.
5 Horn Pieces by Hungarian Composers. All 20th century pieces. Lots of short movements, some of which look to me to be playable at your son's standard. Also Ed. Musica Budapest.
You could look at June Emerson's on line catalogue for more ideas. Everything has a suggested level of difficulty. Those books may even be listed.
Good hunting!