With the first question what it sounds like you want to do is open your image (you may have to copy and paste it into a new document, not sure)…
Select the layer with your image then go to Image/Adjustments/Hue Saturation (this is in Photoshop 7, it is still under the Image menu in 6, but Adjustments was named something else, which I forget now)
Then check the colorize checkbox and slide the sliders to the color you want.
As for your second question, yes it is possible. You can use the Lasso tool. If you have the toolbar pallette open, it is the tool right under that Rectangle Marquee tool. You can right click on the lasso tool to choose between 3 different types of lassos. The rounded one is to select an area freehand style, the jaggety one is to select an area by clicking points, and the one with the magnet allows you to better outline things.