Hey, Rdooms! Welcome to the wonderful world of getting yur arse up a tree! Since your new to climbing, I'm guessing your working for someone, and probably using his climbing gear.
My advice would be to buy your own personal climbing gear ASAP. Use his stuff for awhile to get a feel, maybe, for different types of equipment, but as soon as you think you know what you might like, and you've got the bucks, PURCHASE YOUR OWN GEAR.
You've got a lot of READING to do, starting right here, at this site. Grab a cold one, get comfortable, and begin to read all the threads. Start with the Accident/Fatalities section. READ! Then, move on to the Climbing section. USE the search function. Allmost any question you can come up with is more than likely in there. In other words, MORE READING.
Use your credit card to immediately order the Tree Climbers Companion, as Brian suggested. Thats the first book. There will be more to come. These forums, plus that book, will lay a good foundation for this new challenge you've chosen to undertake.
I see your not quite the spring chicken, as well I. Get strong. Stay strong. Get stronger. Get lean. You wouldn't believe how much more work it is(ESPECIALLY TRIMS) if your packing poundage you don't need.
Welcome to the club! Maybe, you'll be......
THE ONE!!!