Looking to set up dual monitors

Ive had a 15 inch LCD sitting around for a while, and now im looking to set up a dual monitor display. Ive got an ati radeon 9600 AGP card, afaik it does not support dual monitors. From the googling i did, it seems i can plug the 15'' monitor into my mobos native video. Is this correct?
Assuming this is correct, would i then just reboot (thats what it seems), or do i have to install anything? (thinking of getting ultramon, but is it necessary?
Also, would this leave my radeon as my primary graphics card? (the 19'' LCD is plugged into the radeon)

Thanks in advance

Correct, Not Necessairly, No, Yes

Windows will detect it and you can change the properties in the display properties box.

Usualy, if your motherboard has the ATI Radeon 9XXXIGP chipset (X denoting some chip number). Then it can be set up for the video to output from motherboard and video card. The ATI bios on the MB must be udpated as well. I'm assuming you have an ASUS motherboard?

In order for what you want to work, MB chipset must be ATI IGP and the video card must also be ATI (which you have) .

In the BIOS setup screen, you can set the function from there, assuming you have updated the BIOS; the factory installed bios has this featured disabled/removed.