On his Northwest Weather Blog Cliff Mass has two blog posts up regarding the unpronounceable (and nearly unspellable) Icelandic volcano, here and here. In both posts he takes great effort to make clear that the eruption will not have any long-term climate effects.
While I know nothing about meteorology compared to Mr. Mass, I think he should take care to hedge his bets some, if for no other reason than it is entirely possible that the current eruption of Eyjafjallajökull* could go on for weeks, let alone that there seems to be well-founded fear that "Volcano E" could be joined in erupting by one or two other nearby Icelandic volcanoes, one of which last erupted in 1783 and caused severe winters in North America and Europe, and indeed is credited with causing weather conditions (and subsequent harvests, etc.) that contributed to the French Revolution.
Instapundit links to a time-lapse animation of the spread of volcanic
Feel free to deem this hedging my own bets on the long-term impact of the eruption; might be largely restricted to commercial airlines (other tour and travel industries in Europe are making up in extended stays what they are losing in turnover) or, if it goes on long enough, especially if one or more other volcanoes also erupts, it could be have a severe global impact.
Note that the animation I linked to above on the Map Room apparently shows the plume doubling back to, or toward, eastern Canada...
This second (chronologically, first) post on The Map Room has links to other imagery, including some from NASA.
And, of course, in some corners we are seeing comments like "This is just Mother Earth/Gaea/The Goddess (sometimes all three) reminding us who's boss." Often the same folks who just a few days ago were blaming earthquakes on Glowball Warmening.
By the way, how many folks do you think saw the US Geological Survey's release that the apparent increase in earthquakes is simply the result of more and better monitoring and reporting, not an actual increase in 'quakes, and how many do you think believe it?
****Thank you, Wikipedia, which says it is pronounced [ˈɛɪjaˌfjatlaˌjœːkʏtl̥], which tells me absolutely nothing...