This is good advice, but it needs to be followed only after you know EXACTLY how to perform these exercises. Doing them improperly is just asking for trouble.

You can start by reading "Starting Strength" by Mark Rippetoe. If you don't feel confident that your form is correct, you can join a forum like the one over at stronglifts.com. They will probably be happy to review a video of you doing the lifts to let you know if you're doing things right or wrong (and what to fix, if it's not right).

Although, if you can swing it, I'd recommend finding a trainer to start you off.

I second the recommendation for Starting Strength. Strengthening your entire posterior chain (hamstrings, "glutes", lower back and upper back will do wonders for your back problems.

Having said that, spending 1 hour a day fixing your problem won't be enough when you're spending the other 23 hours undoing it. Sit up straight or do as I did and get a stand-up desk.

This is good advice BUT you really need to increase your joint mobility before attempting these lifts.

I would recommend this series of articles to understand the theory behind bad posture and how to fix it.

http://www.t-nation.com/free_online_article/sports_body_trai...

I would spend at least 2 months just improving your joint mobility (especially hip + ankle) before attempting deadlifts. And even then you should really have someone who knows how to do them correctly to coach you.

Else you'll seriously hurt yourself.

I mentioned this already, but be cautious of full depth if your femurs (upper leg) are relatively long (to your lower leg, not your whole body). Those lengths affect your hip angle in keeping your center of mass (including the hopefully heavy weight you're lifting) over your feet. To get the weight low, long-femured folk are more bent at the hip (back more horizontal).

Enjoy the fact that you have a mechanical advantage in cycling when you're feeling lame for not going as deep.