eXaro it's a free report engine similar to Jasper or Crystal Reports. eXaro can be embedded very easy in any Qt application. eXaro has an integrated preview with search and export (in different formats) capabilities. eXaro came with a visual designer.
It's a great report engine with to potential to became an even greater one. It uses Qt so besides the great integration it's multi-platform! Dual-licenced (GPL, LGPL) which is great for use in both free and commercial apps.