From the Vatican's Bolletino I read that the Holy Father has lifted the excommunications imposed on Bishops Bernard Fellay, Bernard Tissier de Mallerais, Richard Williamson and Alfonso de Galarreta. This is geared towards the reconciliation of their community with the Church.
The Congregation of Bishops explains that this is aimed at strengthening relationships with the Society and is intended to lead to a regularization of their relationship with the Holy See.
Personally, I think that this is a very generous act of the Holy Father, and I hope that no one would doubt his good will and sincerity. It will attract criticism, no doubt, but it's important to understand precisely what this gesture means. It's a gesture of mercy because the excommunications were justly imposed. It's a concrete sign that the Holy Father wants to bring the Society back into communion. However, my understanding of this (and I admit that I'm not a canonist) is that this is simply a starting point. Bishops Fellay et al still lack jurisdiction within the Church and the Society cannot be said to have been restored into full communion. Bishop Fellay and the clergy of the Society are still canonically irregular and do not have faculties to exercise their ministry. Whilst not excommunicate because of their irregular consecration, the Bishops of the Society are not properly members of the Catholic Hierarchy. Membership of the College of Bishops depends, not only on valid episcopal consecration, but also on hierarchal communion with the Bishop of Rome and the other Bishops.
It should also be noted that there is a lot of theological ground which needs to be covered, especially in the area of religious liberty, the authority of the Second Vatican Council and the newer liturgy. The clergy of the SSPX will need to undergo a severe examination of conscience regarding some of the things they have said over the past few years. However, with charity and the work of the Holy Spirit, wounds can be healed.
Edited to add: Amy Welborn does a wonderful job of gathering the commentary on this event together and explaining what's going on. She's also kind enough to link to me. ;)