oh BUGGER just typed a really long post and lost it all dammit
Anyhow, I was one of Patricia's guinea pigs and it really helped me.
Done properly it is NOT money for old rope. Yes, it should be obvious (and is to many people) how to sort your life out BUT if we could all do it we'd all have perfect lives wouldn't we.....fact is it's very hard to bring any sense of perspective to your own life and problems. Also, many people (and often busy mothers trying to run themselves/a house/family/job/whatever) are so busy looking after and organizing other people that a)there's no time to sort yourself out and b)subconciously many people believe they're not actually 'worth' spending time looking at themselvers
It's most important that you pick a coach who you click with and feel you can talk honestly too.
Life coaching will make you look at your life, and any particular decisions/problems you have in a structured way. it will help you prioritize things, sort out what to do when, what's important to you, what criteria you can use to decide things and come up with strategies to help yourself. Essentially it's project 'you' 
hopefully it will also help you apply the skills you learn in the future so you can be a bit like your own life coach. It's massively helpful to get another perspective on your life and to talk to someone to sort your head out when you don't actually need a counsellor, you just need someone to help you tackle all the stuff that gets swept under the carpet.
I have really gone on - just wanted to say I am sure that there are some crap life coaches out there (as in any field) but the concept itself is not ridiculous IMO. Of course Mumsnet is very helpful too, but quite easy to ignore 
. I wasn't sure before I started but it really helped me clarify a lot of things and treat myself better. Well worth it especially if you have tricky decisions to make.