Hey Viking,
Glad you are trying to keep yourself fit
Well if you are a beginner with weight training then keep your session up to 45 min..
I personally train for 1 and a half hours and thats not including cardio.
I suggest for the first three months you strictly keep your session for 45min... 1hr max...
http://www.bodybuilding.com/fun/fawnia1.htmCheck the above link to see which muscle groups go well together... its a pretty decent article.
Regarding sets and reps....
For you first month I would say do a total of 5 exercises per session... so if you are doing chest and triceps on day 1 then do 3 chest exercises and do 2 triceps exercises. Always exercise the bigger muscle first.
Do a total of 3 sets and 15 reps per exercise and take only 30 second rest between each set. Stick to the lighter weights at this stage. The objective right now is to get the movement right. Theres no point doing heavy weights if you are not doing the exercise correctly. There are loads of vids on you tube which show how to do weight training properly. I suggest you check them out.
The reason for the high number of reps and short rest period is to build up your endurance and stamina.... Its gona be tough and your muscles will sore big time the next day.... but man is it worth it....
Once you are more experienced you can move on to heavier weights and do lesser reps... but for now I strongly advice you to do at least 15 reps per set.
Hope this helps. Feel free to ask me any other questions you might have.
Best regards,
Sahil
P.S. Aim for 20 min cardio.... personally I think treadmill/jogging is the best way to shed pounds. Cyclings good too.