Help with Photoshop CS5!?

Select the layer and press CTRL+I to invert it. (making the text white)

Then in the layers panel with the layer still selected. Next to the opacity you should see a drop down menu that currently says "Normal" change that to "Lighten" to get ride of the black on the image and keep the white text.

Ok; from what I see, you haven't placed the image, at the top of the screen there should be a tick button, click it. Now look on your left panel, this is the panel of glory, Here, look for the tool that looks like a magic wand - this is effectively the magic wand tool. click it.

*If for some reason you do not see it, find the quick selection tool (you can see the names of tools by hovering over them) click and HOLD for a moment and you should be given the option to either use magic wand of quick selection. Obviously select magic wand.*

Now, hold SHIFT and left click on the white areas of the image (make sure to click accurately on ONLY the white parts and NOT on the black text YET). This includes the white background in the holes of the letters (like the inside of the 'o'). Use Alt + the mouse scroll to zoom in and out if needed.

Right, that got rid of the white background, now do the same for the black text, select the magic wand and SHIFT + click it to select it. Then select the fill tool (looks like a bucket pouring paint) and select the colour white form the colour selector in bottom of the left panel. Now click on each of the selected letters and BAM, white text. Goodbye.

Hope this helped you!