First is-duh-get the supplies you'll need.
Heat shrink tubing
Piezo igniter from an old fireplace lighter
Pointy pokey thing
Something that will heat-shrink the heat-shrink
A side note: there is another Instructable now by Geoffrito
about how to remove the ignitor.
You don't need to add extensions unless you want to, just extracting the piezo igniter should give you enough length.