The technical corrections to the fractional gift rules that I mentioned last month have now been signed into law. They eliminate the most serious problem with the new rules, what I've been referring to as the mismatch problem (i.e., had the work appreciated in value between the time of the initial gift and a subsequent gift, the excess value of the subsequent gift would have been subject to gift or estate tax). They do not, however, change the requirements that (1) the gift be completed within 10 years (or, if sooner, the collector's death) or (2) the value of any additional contributions be determined using the lesser of the value of the work at the time of the initial contribution or the time of the additional contribution (thus depriving donors of the benefit of any increase in the value of the work over time). So, while the corrections do bring fractional gifts back from the dead (as evidenced by the recent major gift to LACMA), there still remain some disincentives to fractional giving. It's left to the pending Promotion of Artistic Giving Act to address those.
You can read the The Technical Corrections Act of 2007 here.