1. Get plug boot removal pliers ( any auto supply store ).
2. Twist & pull, twist & pull, twist & pull.
3. Get a tube of dielectric grease while you're at the store for your pliers, and apply a small amount of it inside the boots, before you replace them.
What happens is, the new plugwires are installed on the engine during the time of assembly. Within a certain time period, the material of the boot will " cure " and bond itself right to the ceramic on the sparkplug.
The application of dielectric grease will eliminate this, and help seal out moisture at the same time. Try it, you'll like it.