Same Sex Immigration Issues
A placeholder for the rapidly changing laws on same sex marriage and immigration issues associated with it.
 SCOTUS decision
6/26/2015 - In a 5-4 ruling, the SCOTUS ruled in favor of same sex marriages across the nation.
Obergefell v. Hodges 
THESE LISTS ARE OUT OF DATE
1/23/2015 - Alabama, ban struck down.
As of 1/16/2015 - the Supreme court has finally decided to hear four cases on same sex marriage from Kentucky, Michigan, Ohio and Tennessee. Decision expect perhaps around April ish.
As of 10/17/2014 - Probably easier to say which states still have bans in place, some have had pro-marriage rulings issued but further action is pending - AL, AR, FL, GA, KY, LA, MI, MO, MS, ND, NE, OH, SD, TN, TX as well as KS, MT and SC which have appellate rulings against them.
As of 10/17/2014 - Total number of states allowing same sex marriage - 32 + DC
As of 7/10/2014 - 17 states plus DC allow same sex marriages and at least 14 states (Arkansas, Ohio, Texas, Utah, Oklahoma, Virginia, Michigan, Idaho, Oregon, Pennsylvania, Wisconsin, Indiana, Kentucky, Colorado) have had their bans overturned by a Federal judge but some may not allow them during appeal.
As of 10/7/2014 - Regarding appeals: The decision to overturn Utah's ban was upheld by the 10th Circuit Appeals court, this court also has jurisdiction over Colorado, Oklahoma, Wyoming, New Mexico and Kansas. The 4th circuit appeals court upheld Virginia's decision to overturn their ban, also has jurisdiction over Maryland, North and South Carolina and West Virginia. The 7th circuit appeals court upheld the decision to overturn Indiana's ban, also has jurisdiction over Illinois and Wisconsin. The 9th Circuit struck down marriage bans in Idaho and Nevada, jurisdiction over Alaska, Arizona, California, Hawaii, Idaho, Montana, Nevada, Oregon and Washington.
As of 11/06/2014 - Regarding upheld decisions: only one state ban has been upheld on appeal by a District court - Louisiana (9/3). There has since been a second Louisiana District court ruling (9/22) by a different judge that overturned the ban. It is not clear how these conflicting rulings will play out. Other states in the 5th circuit appeals court have cases pending so it may end up being moot. The 6th circuit court of appeals upheld the ban of four states (Kentucky, Michigan, Ohio and Tennessee) overturning lower court decisions that had previously ruled the bans unconstitutional.
As of 10/6/2014 - Regarding appeals to the SCOTUS. Seven petitions to the Supreme court to appeal the decision to overturn their bans were declined. The petitions were from Indiana, Wisconsin, Utah, Oklahoma, and Virginia. Same sex marriages can now go ahead in those states plus Colorado, Kansas, North Carolina, South Carolina, West Virginia, and Wyoming which come under their federal circuits.
All of the individual state bans have now had papers filed to challenge them as unconstitutional. The general trend is that the bans are overturned on equal protection grounds though many decisions are then stayed pending appeal. A notable case is that of Kentucky which currently bans same sex marriages, while the ban itself was not challenged, it was found that Kentucky must recognize same sex marriages from other states where it is legal.
Other states that recognize out of state marriages include: Alaska, Colorado, Missouri, Ohio, Utah
Same sex marriages allowed:
 Interesting cases
Reside in Florida, married in NY 
 UK Same Sex Marriages
It should be noted that the marriage of Windsor took place in Canada. Generally speaking USCIS will recognize a marriage that is legal in the place it occurred.
 Other considerations
While many states now allow and recognize same sex marriages, other legislation may lag behind. For example while the tax issues and hospital visitation rights may have been clarified, rules regarding adoption and anti-discrimination at work may not be resolved for a while. LGBT is not a protected class in statute, though there is an executive order signed by President Obama that bars federal contractors from discriminating.