I've already linked to a very good commentary on the Euro elections from the counter fire site. Here's another useful piece on the results, from Chris Bambery in Socialist Worker.
The most useful thing here is Bambery's rejection of the myth of a shift to the Right in people's ideas, whether here in the UK or across Europe. It's also useful to be aware of the successes achieved by the radical left in a number of countries, indicating that disillusionment with the political mainstream doesn't have to be channelled rightwards.
Even in this country the Greens' success suggests reasons to be hopeful. While they aren't a consistently left-wing pole of opposition to the political Estabishment - and their strongest areas reflect something of a middle class base - their vote can largely be seen as an expression of desire for something to the left of New Labour and Lib Dems (the latter have, under Clegg's leadership, largely dropped the leftish rhetoric of a few years ago). Today's Guardian reported that their best results were in Oxford (26.1%), Brighton and Hove (31.4%) and Norwich (24.9%). In all of these they took 1st place - and by margins of between 6% and 9%. They stand a very good chance of winning parliamentary seats in these areas at the next general election.
The organised left has a long way to go, but there are sound reasons for aiming to build principled and progressive broad alternatives to our bankrupt and discredited elites - and the system they prop up.