I found a really cool tutorial on VectorTuts+ about the flare tool in Illustrator. These brushes are the result of my experiments based on the tutorial mentioned. There are 10 kaleidoscopic brushes created with Illustrator and Photoshop CS3. These are great for use in backgrounds, flyers, cards, etc since they are large, over 1100px.
The brushes are compatible with Photoshop CS3 and above. They are free to use for both personal and commercial projects. Enjoy!