How about the layer you're typing into being visible? I mean, is there another layer on top of the layer you're adding text to?
Have you tried creating a new document and adding text to a file with only one layer and with contrasting colors to the text and the background?
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Olympus C350-Zoom || Canon EOS 300D || Adobe Photoshop CS3 || Manfrotto tripod || Photomatix Pro
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