I am by no means an expert but sound like i am about 3 or 4 months ahead of you on the same journey.
from a few fits and starts i can only offer the following
the main thing starting out seems to be Time In The Saddle. Do not worry about speed, do not worry too much about distance, do not worry about intervals or anything like that, just work on increasing the amount of time you are spending in the saddle each week. (so going slowly for an hour is better than going hard for 30 mins)
pick a time that works for you and try to get out 5 times a week or every day and your body will quickly start to adapt. (a lot of people seem to prefer training in the mornings, tiredness resulted in too many missed rides for me so now I just go each evening after the traffic has died down)
use the web (strava, endomondo, bikely) to find various rides in your area to keep things interesting. i also use endomondo to keep track of my rides. is free, works on your phone and keeps track of where you have been and how long you have been in the saddle (so you cannot lie to yourself). Something like endomondo is also really good for showing progress. I know i said do not worry about speed but sometimes it is hard to notice any improvement and a ride tracking app will show your times improving as you train.
if you are starting out on a new bike and are planning to do a fair amount of riding i would personally recommend getting some form of bike fit to make sure you are set up right to avoid injury.
oh and incorporate some stretching in your routine. getting more flexible again seems to make the whole process a lot less painful.
finally i personally have not tried to meet up with any kind of organised ride as yet. when out on the roads i saw groups of riders and found the whole thing a bit intimidating. too many rules and the feeling that you will not be able to keep up. I enjoy riding on my own as thing that is pretty much the only time i get to myself in a week and think i am fairly good at pushing myself and maintaining a good level. However lots of other people seem to find group rides a real benefit. gives other people to train with, a way to find new routes, lots of people to give advice and encouragement so guess that comes down to personal choice.
oh and just seen the reply above, no matter how much of an idiot you feel i would recommend buying some bike shorts as this will make a massive difference to how comfortable you are, gloves, a helmet (in Oz they are compulsory but i would get one anyway) and some decent lights. A jersey is worthwhile because you can carry stuff in the back pockets (phone, cash, spare inner tube, tyre levers, some form of food will all come in useful). I started out with a jersey (found a cheap place on web which sells them - mupi) a pair of shorts (get from bike shop to make sure fit is right) and clip in shoes and progressively added more gear each month (was winter here so had to add arm and leg warmers and something water proof)