You're probably very familiar with this graph by now. Many have been declaring this a success, and in early 2009 with a statistically significant (outside the margin of error) majority it appeared it was. The trend we're seeing in youth is very promising.
In 2010, however, we've dropped to a tenuous and statistically insignificant plurality. However, from other polls we can learn what types of outreach we should focus our attention on.*
As you can see, 3% fewer people identify as "pro-life" than consider abortion to be "morally wrong". This is within the margin of error, but with the drop being from 50% to 47%, I think it's worth outreach to those "personally opposed" to abortion. SecularProLife.org is already doing some of this by its mere existence, as many religious people are unaware of the secular reasons to be pro-life, and are thus pro-choice due to their beliefs on the separation of church and state. There is also probably significant concern about back-alley abortions, and we definitely need to devote attention to the statistical and philosophical reasons why this is not a good reason to be pro-choice.
What I find more interesting is that 7% more people identify as "pro-choice" than consider abortion to be "morally acceptable". At most, 3% of this difference can be accounted for by the "personally opposed" crowd, meaning at least 4% of the 12% morally undecided/neutral crowd consider themselves "pro-choice". I think this means people don't understand that the benefit of the doubt should go to life.
The demographic differences are less interesting. There is only a 5% gender gap, for instance, on the morality of abortion (women being more against it), but very slightly (1%) less likely to identify as "pro-life". In addition, Republicans and Democrats have become more pro-life and pro-choice, respectively, but it's hard to know if this is an actual change in anyone's opinions or just a result of pro-life liberals feeling not welcome in the Democratic party.
What I find most interesting is the role education plays in the legality polls, with graduating from college (especially among women) being correlated to support for the "legal under all circumstances" view of legality. By emphasizing the scientific/biological and philosophical arguments against abortion, SecularProLife.org also helps address this issue.
In summary, if we take the current 47% pro-life plurality, and manage to get people to vote their consciences (+3%) and give the benefit of the doubt to life (+12%), we should get a sizable (62%) pro-life majority without actually having to change anyone's mind on the morality of abortion!
As demonstrated by this graph, those who view abortion as morally acceptable have been consistently in the minority. Even when those who view abortion as morally wrong were below 50% (2001, 2006, & 2008) or at 50% (2004 & 2010), everyone against abortion voting their consciences and everyone with no opinion giving the benefit of the doubt to life would bring a sufficient majority to protect the rights of the unborn.