There is a shrine to Saint Jude in Illinoise, and they publishe some prayers on their web site. There is also a collection avialble in a booklet fromTan publishers. Quite a few prayers to St. Jude exists.
The church has never said anything aganst praying to a saint, nor against evangelizing the intercession that praying to siants yields. But I think the type of devotions that have “chain letter” aspects to them, such as "distribute x amount of copies of these prayers, (as opposed to the general “make known that God works wonders throught he intercession of St. Jude,”) do not sound very sound.