Tradition: Oral and Written

I am a Protestant Christian.  I believe the Bible is the foundational, indisputable rule for the Christian Life.  As a Protestant, then, I had to take pause at a verse I never read before (or at least one that I simply did not remember):

"So then, brothers and sisters, stand firm and hold fast to the traditions that you were taught by us, either by word of mouth or by our letter." - 2 Thessalonians 2:15

What caused me to take pause was not the fact that Paul urged the Thessalonians to remember and obey the things he shared with them on his visit(s), but that he referred to them as "traditions."

Most radio preachers speak of tradition as if it were a four letter word. From my seminary training at Fuller Theological Seminary, I have come to accept that word (as well as "religion") as an acceptable, and indeed positive word in a Christian's vocabulary and Church History. However, I'm not sure if I accepted the legitimacy of Apostolic oral tradition until I read this verse today.  Many questions come to mind:

1. Where do these oral traditions originate? From Paul's ministry team, or did he receive them?
2. Are these oral traditions completely distinct from the written ones given to the Thessalonians ("...by our letter")? The verse seems to suggest this, however 2 Thessalonians 3:10 is an example where oral and written tradition overlap.
3.  Could one church's written tradition be anothers' oral tradition (and vice-versa)?

Lastly, Protestants enshrine written tradition and are to varying degrees skeptical of oral traditions.  But, 2 Thessalonians 2:15 seems to hold them on the same level, at least in Thessalonica. I believe there is good historical reasons to privilege written tradition, but might it be possible that oral traditions should be given more respect than they current hold in Protestant circles?

In his written tradition, Paul does not seem to make mention of any material or spiritual difference between his oral and written traditions. This leads me to believe that the key issue must always be authority, and Paul links the authority of his oral and written traditions in 2 Thessalonians 2:15 with their origins in the Apostolic team.

It seems to me that the "platform" (i.e. written or oral) must be a secondary issue. The primary issue must be origin.

But questions remain:

1. How can the origin of oral tradition be reasonably established?
2. If Apostolic origin is the key, does that mean that everything the apostles every said or taught orally was always correct? (we hold this standard for what they wrote – i.e. the scripture)
3. If the apostles were infallible in what they wrote, and the platform of the written word does not make their teaching any more legitimate, does that mean that they must also have been infallible in what they taught orally?
4. The Holy Spirit and the Gospel message gave birth to the church (Acts 2), the Apostles (Acts), and the written tradition–i.e. scripture–and oral tradition. To what extent can the Holy Spirit and the Gospel message be used to test the orthodoxy of oral traditions circulating today?