Locating Birth, Marriage and Death records in New Jersey for the colonial period can be time consuming and even frustrating. There were many congregations of various denominations throughout the state, many of them small, some of them fleeting. Often a family that is the focus of one's research is found to have different children baptized in different churches. This can leave you with the impression that you can never feel confident that you've found the records for every member of a family until you've identified and searched every possible location. Then comes the problem of locating the published records of the churches that you wish to search. Many were published years ago in Genealogical or Historical Journals with limited circulation. Not every library carries the issues of the Somerset County Historical Quarterly, for example.
Fortunately we now have the internet. And we're even more fortunate in that we have many people who have taken the time to place online records and transcriptions of records from many of the smaller churches in New Jersey. Here then are a few links to websites that are nice to have at hand. None of them are mine. All are the efforts of others, so a thank you to all who took the time to create these sites.
Bergen County Marriage Index
BMD of Sussex County and Surrounding Areas
Piscataway, N. J. Register of Births
History of the First Baptist Church of Piscataway, Pioneer Biographies (no VRs, but useful and works hand in hand with the link above)
Stone House Plains Dutch Reformed Church, Bloomfield, N. J.
Second River Reformed Dutch Baptisms
New Brunswick Reformed Dutch Church Marriages, 1794-1799
First Reformed Church, Raritan (Somerville) Baptisms, 1699-1745
Nancy Pascal's Genealogy Page: Sussex County and Surrounding Area
In addition, as many of you know, Family Search is in the process of placing online many records previously available only on microfilm. As luck would have it, New Jersey appears to be one area that received early attention. This link, Searchable databases for New Jersey at Family Search, will get you started. Included in New Jersey Births and Christenings, 1660-1980, are the records from the Freehold-Middletown Dutch Reformed Congregation in Monmouth County.
I'll end with one important caveat. All of the above, including the Family Search databases, are transcriptions of transcriptions. They are at least two, and perhaps more, "generations" removed from the originals. With every new transcription comes the increased chance of error. It is advisable (mandatory if you are considering publishing your work) to seek out the earliest and/or most reliable source for each record. The links above, however, are valuable in providing quick answers and a start on where, or if, to search for a more "reliable" copy.