Can anyone give some guidence?

I want to use a GUID as the primary key in my data tables. The project
is in its early stages and I have been using a VarChar to store the GUID.

As part of the feasibility testing I inserted one million records into
a table. A simple SELECT query took 6 seconds to return a result, very
impressive, considering it was done on a 2100+ AMD with 512 MB.

But...

My question: Is there a more efficient way that I can use GUID's. I
have read on this list people achieving sub 1 second transactions.

Thank-you In Advance

Luke