For Samsung Captivate owners it was a struggle just to even get Froyo, let alone Gingerbread but thanks to some leaks -- there is now a pair of official-looking Gingerbread 2.3.3 leaks available. Both have different build dates with the later build addressing minor fixes over the older build.
- I897UCKE3 - Build date of May 26, 2011
- I897UCKF1 - Build date of June 8, 2011
As folks have been ripping through them to find changes, it's been noted that AT&T bloatware is present in each in one and both appear to be making use of a new bootloader similar to that of the i9000. As with all leaks -- you'll have to exercise some caution should you go messing with these, they're not meant for everyone and just because they are labeled "official" does not mean they're ready for prime time. Until released by an official carrier -- they're still just leaks.
That said; if you're into dealing with the nitty gritty details and comfortable going hands-on with Odin in order to get either one of these files loaded up you can hit the source links for more details.