Play around with you tube for instructional videos and sleep has recommended a great book. You want to be strength training 2x per week if you can and work on lower reps with heavier weights - 3 sets of 5/7 reps, at a weight that you can only just finish them (with good form). Always include a squatting move and stick to other compound moves to get more bang for your buck. For example, one of my fave strength workouts would be 3x5 back squat, 3x5 deadlift, 3x5 shoulder press, giant set with 3x5 pull ups/10 push ups/10 lateral raise/10 front raise. I would finish this with a quick 4-7 min metcon eg a tabata alternating kettlebell swings & squat jumps or something like that.
Personally, I love to lift heavy but I do also love a good fairly heavy circuit too.
Form is critical, especially when you´re learning the lifts. If you can get a couple of sessions with a personal trainer just to give you a good grounding in technique, I would highly recommend it.
Most of all, have fun. There is nothing like lifting heavy to make you feel AWESOME!
Re resources, the book, New Rules of Lifting for Women comes highly recommended. There are lots of things on youtube showing techniques, not sure about apps though.
Re 5kg, that isn't too crazy but it also depends what you are using them for! Squats should be easy enough, shoulder presses will be hard straight from 2.5's! So definitely start with very low reps and see how you feel, even if it seems ok at the time you may ache a lot the next day or so.
I currently do cardio three or four times a week to great success (have increased stamina/fitness and am losing weight) but now I want to build up my muscles so I can burn more weight at resting level (as well as to get stronger!).
I used to do a lot of light weights with many repetitions but this is just like cardio so I'd like to do a shorter routine using heaier weights and fewer reps.
I only have my husband's dumbbells in the house (no barbells) and they start at 5kg. I'm used to 2.5kg but doing 10-15 reps of these. Should I start my programme using 5kg and 3x6 reps? What have you done?
Also, are there any good apps for iPhone/Pad focusing on weights (for women?) with video to show the moves?