Over the past two years I became addicted to National Public Radio (NPR) podcasts. I was already a devoted listener to their radio programming on WNYC, my local station. But there are more programs produced by NPR than could fit into any one station's scheduling each week. The podcasts solve this problem. Then the only problem becomes finding enough time in your own schedule to listen to all those you download each week! At my last job I was able to listen on my iPod while doing my work, which was a real treat.
One podcast I listen to is All Songs Considered. The host, Bob Boilen highlights all kinds of new music every week and sometimes has special episodes that focus on discussion of a particular topic with other music critics. They also offer podcasts of many, many live concerts by all different artists, which I find to be a great way to learn more about their music before I commit to getting their albums. Did I mention all of this is FREE?!? There is no charge for any of the NPR podcasts, but it is nice to make a donation to your local station every once in a while, if you can.
Right now All Songs is offering a free (yes, free) download of a 10-song sampler. The songs are all by artists who will be performing at this year's South by Southwest (SXSW) music festival. I highly recommend getting this playlist. It's full of varied and interesting music. You must have iTunes in order to get the songs, but I think it would be worth downloading the program for this even if you don't yet have it.
PS: If the sampler isn't enough music for you, you can also listen to a stream of 100 songs by SXSW artists on the All Songs site!