Photoshop :: Drawing Lines - How?

I am quite new to photoshop and am working through a few tutorials. In one of them it asks me to draw a line. Now I thought this would be really easy.

I clicked the Line tool and tried drawing it where the tutorial said, but all i got was a selected section and in the layers window it showed something about a mask. According to the tutoria it shouldn't do this.

I undid it and tried again, still the same problem. I tried deleting the mask and the work area just goes black.

Can someone please tell me how to create a Line without the whole mask businees.

P.S: I am using Photoshop CS on Windows XP.