Ulead offers some free Photoshop compatible plugins if you sign up to become a member ( free , except for the cost of probable future advertisement email anyway).
I've downloaded the Particle plugin, and successfully used it in Xtreme.
The effects include: Bubble, Firefly, Rain, Snow, Cloud, Smoke, Fire, Star.
Here is an example using the Bubble effect.
Go to www.ulead.com , then to the Free Goodies section under Download.