Actually, that's not true. Most battery replacement kits come with plastic removal tools that work fine, though they (the tools) often become damaged in the process. The instructions are simple, and anyone with an average amount of patience and coordination can do it in minutes. I've done it myself on a 3g, and the results were perfect. No difficulty whatsoever.
If you've got jelly hands or are clumsy, easily frustrated, or otherwise lacking manual dexterity, just give it to your friend to do for you.