Charles Savelle on his blog Bible X informs us that Southwestern Baptist Theological Seminary has posted audio sessions from the 2009 Expository Preaching Workshop. In particular, David Allen has a session on "Preaching the Difficult Passages of Scripture - Hebrews 6:1-6." In short, he argues that the passage is not dealing with salvation, but Christian maturity.
Alan Knox offers a brief reflection on the necessity of mutuality based on his research on the theology of encouragement in Hebrews.
Michael Bird gives a Good Friday meditation on Hebrews 2 using the analogy of tasting tabasco sauce.
A number of blogs have been noting that SAGE publications is offering free access to all their journals until May 31. There are a number of articles and book reviews on Hebrews that are available. I will not list them here since free access is only temporary, but a simple search will easily find them.