If you have ancestors in West Virginia, there is a great genealogy resource you should know about. The West Virginia Archives and History has placed a large number of vital records (birth, marriage and death) online as part of their Vital Research Records Project. The dates you can search vary by county, but most counties have records going back to the 1800s. Birth records go to within 100 years of today's date, with subsequent years being added as they pass the 100 year mark. Death records go to within 50 years of today. As with birth records, subsequent records are added yearly as they reach that mark.
Some of the records are transcribed. On others, it will be necessary to view the image itself to get your information. If you are looking for siblings of an ancestor, it pays to scroll through the entire page your ancestor is listed on. In many cases, I was able to find siblings a couple lines down.