I would strongly suggest learning how to do it properly. Do you
know anyone local who can show you? It's not difficult, but it's
something you really need to see and feel being done, and not
just read about.

Dave
I am that man. I was shown how to do repointing by a builder when I
had my first house and had to repoint the chimney. As others have said
don't worry too much about getting all the old cack out, just the
loose bits. The way I was shown was to use the pointing trowel and get
a small triangular fillet of mortar onto the back. I use a homemade
mortar board to hold a big blob of mortar. The fillet of mortar is
then pushed into the gap. Once you have filled a long length you then
need to finish the pointing. This is a good link that shows the
different types.
http://diydata.com/techniques/brickw...g/pointing.php
I have always used the 'hollow key' method, although I will have to
admit I didn't know it was called that.
I have done this by using a short length of hose to do the finish.
I will happily give you a demo, just give me a call over the weekend.

Tim