Whats the difference?

I was looking at buying a microchip for LED project, and I noticed when I searched for "PIC16F628" I got tons of results for chips including:

PIC16LF628-04/P
PIC16LF628-04/SS
PIC16LF628-04I/P
PIC16LF628-04I/SO

What I want to know is, is there a major difference in these chip's designs? I'm guessing no, but the tutorial I'm using uses a PIC16LF628, and it doesn't say anything about extensions or anything... It also supplies assembly code to work on that chip, will I have to modify anything? I sure hope not. Will there be extra leads on the PIC that I'll have to design into the circuit? Thanks!

--mindctrl

If you live in The US or Europe they have free samples..
Get the 16F628A its newer ..
**broken link removed**
this page describes the different packages...
the /p is a DIP package
the /SO is an SOIC package..
also
the code will be the same for all 628s

Great, thanks. I ordered some samples and am eagerly awaiting their arrival so I can get to making this thing.