Cool. Am trying to develop a more regular practice. Off to try some now.
Here's a couple of tips which helped me:
Keep at it. Even if you don't feel any benefit initially it isn't wasted because you'll get the benifit of what you may consider 'wasted time' in future meditations (so Dave the Budhist guy told me).
Posture is vital; though uncomfortable to begin with; modern day lifestyles lead us to slouch which isn't good for you. You don't have to feel comfortable. Five year old kids can sit for ages with straight backs, but as we get older our muscles change, but with regular meditation with good posture, you muscles will strengthen and it will feel comfortable.
And regular short periods of meditation is better than one long one. For example 2 x 15 minute periods of meditation is better than 1 x 30 minute one.
Oh, and I sometimes meditate at lunchtime and it really perks me up for an afternoon of graft, but it sometimes gets a bit noisy with traffic where I park, so I've down loaded some binural beats to an MP3 player (google for it; there's loads of free downloads) and I like them. There's medical evidence to show binuaral beats work in changing your brainwaves; and it blocks out any ambient noise.
Enjoy it! It gives me a break from the committee in my 'ead!