For mutli-state research, you should start with the Subject Compilations of State Laws: An Annotated Bibliography, by Cheryl Rae Nyberg.     A tutorial of that database is available here.  You may wish to consult a database such as Westlaw or LexisNexis, which will let you search across multiple jurisdictions.  In addition, Lexis and Westlaw provide 50 State Surveys, like the National Survey of State Laws.  Other works we recommend are:

State Call Number Title Guide Print Cases Print Statutes Session Laws Public Sites
KFA Alabama
(KFA)
HeinOnline (1817 - 2010)
KFA Alaska
(KFA)
HeinOnline (1913-2011)
KVH American Samoa
(KVH)
Research American Samoa Reporter LLMC American Samoa Digital
KFA Arizona
(KFA)
KFA Arkansas
(KFA)
State Call Number Title Guide Print Cases Print Statutes Session Laws Public Sites
KFC California
(KFC)
HeinOnline(1849-2010)
KFC Colorado
(KFC)
HeinOnline (1859-2011)
KWC Commonwealth Northern Mariana Islands
(KWC)
Research
KFC Connecticut
(KFC)
HeinOnline (1672 - 2010)
State Call Number Title Guide Print Cases Print Statutes Session Laws Public Sites
KFM Maine
(KFM)
Maine's Revised Statutes Annotated (West)
KFM Maryland
(KFM)
West's Annotated Code of Maryland HeinOnline(1692-2010)
KFM Massachusetts
(KFM)
Massachusetts General Laws Annotated (West)
KFM Michigan
(KFM)
Michigan Compiled Laws Annotated (West) HeinOnline(1806-2010)
KVS Midway Islands
(KVS)
Research Establishment of Midway Islands National Memorial S1098
KFM Minnesota
(KFM)
Minnesota Statutes Annotated (West) HeinOnline(1850-2011)
KFM Mississippi
(KFM)
Mississippi Code Annotated HeinOnline(1799-2009)
KFM Missouri
(KFM)
Vernon's Annotated Missouri Statutes
KFM Montana
(KFM)
Montana Code Annotated HeinOnline(1864-2011)
State Call Number Title Guide Print Cases Print Statutes Session Laws Public Sites
KFN Nebraska
(KFN)
Revised Statutes of Nevada HeinOnline(1855-2011)
KFN Nevada
(KFN)
Michie's Nevada Revised Statutes
KFN New Hampshire
(KFN)
New Hampshire Revised Statutes Annotated
KFN New Jersey
(KFN)
New Jersey Statutes Annotated
KFN New Mexico
(KFN)
Michie's Annotated Statutes of New Mexico HeinOnline(1846-2010)
KFN New York
(KFN)
New York Consolidated Laws
KFN North Carolina
(KFN)
The General Statutes of North Carolina Annotated
KFN North Dakota
(KFN)
North Dakota Century Code HeinOnline (1889-2011)
State Call Number Title Guide Print Cases Print Statutes Session Laws Public Sites
KFW Washington
(KFW)
Revised Code of Washington Annotated HeinOnline(1854-2011)
KFW West Virginia
(KFW)
Michie's West Virginia Code HeinOnline (1861-2010)
KFW Wisconsin
(KFW)
West's Wisconsin Statutes Annotated HeinOnline(1836-2009)
KFW Wyoming
(KFW)
Wyoming Statutes Annotated HeinOnline(1869-2011)