Infrared lasers are the only ones that emit infrared light. *Some* cheap green lasers may leak some, but it won't be collimated/focused, and there won't be much of it. In fact, if it is a quality laser, I daresay it won't emit any IR at all. So I would probably recommend that if you don't want to build one yourself, just hope on over to the Buy/Sell/Trade section, post a WTB: IR laser topic.
If you can solder, you're perfectly capable of making one yourself. How much power do you need? I'm not sure of the required thresholds, are you looking to be able to see the beam in the IR camera or just see the dot in the IR camera? If it's less than 200mW, you can order a diode Here---->
http://stonetek.org/shop/ under "Diodes". So if you just need 5 or 10 mW of 808nm IR, that diode is less than $10, and you can put it in a pointer for another $5 or $10 for the cost of a proper driver plus the cost of whatever host you want to use, and you can set it to give you any power that you want up to the maximum of 200mW. Also, that diode is 808nm, so at high powers, the dot may actually be partially visible to your eyes. I'm really not sure about how an IR camera would handle the 808 specifically, but a lot of normal digital cameras can actually see it better than your eyes can.
Also, if you're going high in power, remember SAFETY. I'm sure you've looked at the dangers or IR light, but just remember with high-power collimated light, you're entering a whole different world than just IR LEDs. 200mW of IR, even from just reflections, can damage your eye faster than you can blink, and you'll never know it until it's already too late and your retina is scorched. I highly recommend safety goggles and other safety precautions (especially if taking it to your high school) if you've never used such things before. 808nm may be barely visible to you as a deep red, but it's visibility doesn't match its true potential for damage.
