If your ancestors are from the Banat region of Europe, currently divided between the three countries of Romania, Serbia and Hungary, it can sometimes be difficult to trace these individuals prior to their arrival in the United States. I ran into this problem myself with my husband's paternal line. Thankfully, there are some free genealogy resources that may be of assistance.
The first difficulty you may encounter is locating your ancestor's village or town. This is because names changed over the years and there may be several variations in the name depending on whether you are looking at the German, Hungarian or Serbian name. The village may also be in a different country than it was when your ancestor left.
The German Genealogy site for Banaters has a nice village list which gives you these alternate names. The list also provides some basic information on the village such as population, current country of location, postal code and railroad station. As an added bonus, it also lists the available genealogical records, many of which can be viewed at your local Family History Center.
The Donauschwaben Heritage Society is another nice free genealogy resource. The mailing list is active and the participants are both helpful and friendly. Thanks to some of the participants on the mailing list, I am finally making progress on a long-standing brick wall. There are also recipes, history, photographs and stories from the region. In addition to the mailing list, you can also join the research exchange to find others that are researching the same names and post information on your own.
The Dreyer Database is a nice resource to help you find your immigrant ancestor. Scroll the yellow column on the left down about halfway to access the database. You can view by immigrant surname, village name, ship name or destination. Some entries are basic, but others have additional information added such as the name of parents, spouse or children; birthplace or date; previous visits.
Donauschwaben Village Helping Hands is another free genealogy resource to check. It has a village index, biographies of some individuals from the region, history, maps, research and more.