Here's my 1st tut:

Open your current sig.
Click on the Type Tool
Type anything thing,like "mAbOK"
Make another 2 duplicate layer. [shown below]



Now:
Click the 2nd text layer.
Goto: Filter>Blu>Motion Blur
You'll see a pop-up warning about rasterized it. Click OK. [shown below]



Follow the instruction. [shown below]



Change the Angle and type 0/180 degree(s).
You can play around the Distance but i always use 20 pixels.

After you've done that,
Repeat it in the 3rd text layer
But this time,try use the Angle 90 degrees

Result:
see my Inuyasha Sig.