printf() with the "%s" format expects an argument of type char*,
which must point to the first character of a string.  printf itself
will dereference this char* pointer to extract and print the
characters of the string.

Incidentally, "%p" is the correct format for printing a pointer
value, but it expects an argument of type void*.  If you want to
print a pointer of some other type, you should cast it to void*.

Finally, some style points (oh, here goes Keith with his "style
points" again).

"l" isn't a great name for a variable; it looks too much like the
digit 1 (and can be indistinguishable in some fonts).

Some would argue that modifying a function argument is poor style.
I don't agree, but modifying argv while leaving argc alone is odd.
An idiom I've seen for traversing command-line arguments is to
increment argv while decrementing argc.  Or you can just use an
integer to loop through the arguments, leaving argc and argv alone.
(If you're concerned that indexing will be slower than stepping
through with a pointer, don't be; the difference will be minimal,
and a good optimizing compiler will likely generate the same code
either way.)

Of course none of this is a big deal for a program this small, but
small programs are where you should start to develop good habits.