It could be, and probably is, dust. Some cameras, especially ones with built-in flashes, will illuminate dust floating in the air near the lens, and these often show up looking similar to paranormal "orbs." Especially since you only started getting them with the new camera.
The best "real orb" shots are the ones where the orb appears to be moving. Or shots taken without a flash. The best way to avoid dust orbs when taking flash photos is to use a separate flash, away from the lens. Either a flash mounted to the camera's hot shoe and angled up, or a flash that is held separately from the camera. Or try and use illumination other than the flash (turn up the lights).
In the case of real orbs, usually one orb represents a single spirit, though a spirit can use energy to manifest itself in other ways, such as ectoplasm or apparition. These are more rarely seen in photos.
If you think you really have a spirit or spirits in your home, try asking them if they want to get their picture taken, and then take a picture, preferably in the daytime without the flash. Then if you get an orb, or a small number of them, they're more likely to be genuine and not dust.
[ December 30, 2004, 11:04 AM: Message edited by: Kevin P ]