...Is there room in photography where something is better than nothing?
Absolutely! I'm one of the very vocal "Don't tackle weddings if you don't know what you're doing" members here, BUT, I also recognize that there are many people out there who cannot affort $5000, $2000, or even $500 for wedding photography, and if you want to shoot those to gain experience and help the couple, that's great, BUT.. a word or two of caution in your shell-like ear: PROTECT yourself. Draft up a contract and have it reviewed by a competent lawyer. Even though you may be doing it for nothing, ensure that you have a signed document which states clearly that you are NOT a professional, and that you are doing this ONLY to help the bride and groom and what you give them is what they get and that's ALL they get. No promises, no guarentees, etc, etc... You only have to search about two seconds on line to find thousands of 'bridezilla vs. photographer' stories (and by stories, I usually mean lawsuits). You will find that in almost all the cases where it went the photographer's way, he had a professionally drafted contract.
As far as second-shooting, don't e-mail, don't text, don't telephone (except to ask for an appointment), TALK FACE TO FACE! Go around, knock on doors, visit other photographers, don't be afraid to start off as an intern (Read: gear schlepper, floor-sweeper and lens cleaner). If I were to hire a second/assistant, there's ZERO chance that I would from an e-mail, but if you take the trouble to visit me, show me a portfolio, and explain what you want to do, there's a MUCH better chance...