On the font use Stroke Layer Style. Use 1 px, and set it to outside usually. For the entire sig, create a new blank layer, select all, go to Edit... Stroke. Choose your color and width.
To do the effect I was talking about, create a new layer, hit Control + A (Select all, Command A for Macs I think), then go to edit... Stroke, choose white and 2px, then click OK. Then go back to Edit... Stroke and this time use 1px black and click OK.
Oh yeah, make sure you are set to inside mode on the stroke window.