The operating system version (10.2 for you) doesn't matter for determining what video card you have: if you follow the instructions Barbara gave above, you can open up the "system profiler", which should give you a window, where you can click on "PCI/AGP Cards" or "Graphics/Display" to see what your video card is.
Basic information on your machine is available in the "About This Mac..." window that you open from the Apple menu as part of this process.
I've attached a screenshot showing both windows -- just click on "attachments" to see it. The important information is the "VRAM" listed under the video card, and the "Memory" listed in the about his mac window. (Click on "attachments" above to view)
-- jen
Attachments
28136-sys-specs.png (112 downloads)
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It is pitch black. You are likely to be eaten by a grue.