Decision just announced. Mandate constitutional; ACA survives intact.
Biggest surprise may be that Chief Justice Roberts voted for the majority, saving Obamacare.
From Scotusblog , reading decision:
"Our precedent demonstrates that Congress had the power to impose the exaction in Section 5000A under the taxing power, and that Section 5000A need not be read to do more than impose a tax. This is sufficient to sustain it."
From Scotusblog :
On the Medicaid issue, a majority of the Court holds that the Medicaid expansion is constitutional but that it w/b unconstitutional for the federal government to withhold Medicaid funds for non-compliance with the expansion provisions.
The key comment on salvaging the Medicaid expansion is this (from Roberts): "Nothing in our opinion precludes Congress from offering funds under the ACA to expand the availability of health care, and requiring that states accepting such funds comply with the conditions on their use. What Congress is not free to do is to penalize States that choose not to participate in that new program by taking away their existing Medicaid funding."
Could mean some tinkering with the law is forthcoming regarding expanded Medicaid.
If I am understanding the good folks at Scotusblog , ACA "mandate" does not survive under the commerce clause but must be redefined as a tax and falls within the federal government's taxing authority.
Justice Kennedy in dissent declares: "In our view, the entire Act before us is invalid in its entirety."
The decision has been posted at http://www.supremecourt.gov/opinions/11pdf/11-393c3a2.pdf 
The following statement is being released by Sr. Carol Keehan, DC, president and chief executive officer of the Catholic Health Association of the United States (CHA):
The Catholic Health Association is taking time to carefully read and evaluate the Supreme Court’s decision on the Affordable Care Act (ACA) and may have additional comments once our review is complete.
We are pleased that, based on an initial read of the ruling, the ACA has been found constitutional and will remain in effect. CHA has long supported health reform that expands access and coverage to everyone. We signed onto amicus briefs encouraging the Court to find in favor of the ACA’s individual mandate and the Medicaid expansion.
As the ruling is examined, Catholic-sponsored health care providers will continue to lead health care transformation – finding new and better ways to provide compassionate, high- quality care while strengthening the communities we serve.
In the coming weeks and months we will continue working closely with our members, Congress and the Administration to implement the ACA as fairly and effectively as possible.
U.S. bishops' conference, which took no position on issues before the court, will not join efforts to repeal the law, still urges legislative remedies to "repair" ACA:
First, ACA allows use of federal funds to pay for elective abortions and for plans that cover such abortions, contradicting longstanding federal policy. The risk we identified in this area has already materialized, particularly in the initial approval by the Department of Health and Human Services (HHS) of "high risk" insurance pools that would have covered abortion.
Second, the Act fails to include necessary language to provide essential conscience protection, both within and beyond the abortion context. We have provided extensive analyses of ACA's defects with respect to both abortion and conscience. The lack of statutory conscience protections applicable to ACA's new mandates has been illustrated in dramatic fashion by HHS's "preventive services" mandate, which forces religious and other employers to cover sterilization and contraception, including abortifacient drugs.
Third, ACA fails to treat immigrant workers and their families fairly. ACA leaves them worse off by not allowing them to purchase health coverage in the new exchanges created under the law, even if they use their own money. This undermines the Act's stated goal of promoting access to basic life-affirming health care for everyone, especially for those most in need.
According to the bishops, "The decision of the Supreme Court neither diminishes the moral imperative to ensure decent health care for all, nor eliminates the need to correct the fundamental flaws described above. We therefore continue to urge Congress to pass, and the Administration to sign, legislation to fix those flaws."