Interlux Brightsides is a good choice. It is a linear polyurethane, like AwlGrip, but it is a single part. If used on the exterior, it would not have the same quality and durability of a 2 part, but it's perfect for inside. If you use this product, properly thinning it will be critical to avoid brush marks.
To apply, roll it one with a small foam roller and tip it out by softly dragging a dry paint brush through the paint. If you feel the brush drag, add more thinner. If you get runs, wait a few minutes for some of the thinner to dissolve.
As this is an interior application, purchase the flattener and use plenty of it. You will get a far more appealing paint job if it's not glossy.
[This message has been edited by Jason King (edited 03-14-2008).]
