Technology is a wonderful thing, and is extremely useful for Christians. It gives us access to countless Bible study resources for free, different translations, concordances, Bible dictionaries, even some commentaries. It also gives us access to some really great preaching from the likes of John Piper, Tim Keller, and any number of others depending on your personal preference. There is a great danger here though, which we all need to guard ourselves against.
These preachers are not actually here.
Obviously I dont mean theyre dead, I just mean that arent here right now in the same place as you. They dont chat to you after their sermon, you cant ask them questions about the bits you didnt understand, and they dont see you during the week or next Sunday and ask you how youre doing. Listening to sermons outside of the context of Church can and should be a great blessing. Its a wonderful thing that we have such ready access to such great Bible teachers. But we must always remember that God designed Church to be Church, not a digital download straight to our iPods.
Sermons do not sit alone in the life of a Church, they are complemented by fellowship, by conversation, by applying what we hear to our lives during the week. We do that application together with the other people in our Church. When we get it right we rejoice together, when we get it wrong we mourn together, and pick each other up.
By all means listen to great Bible teaching wherever you can get it, but dont forget about your Church in the process.
For some more on this, here is a great post on the subject from the Pyromaniacs.