A Dictionary of English Surnames - P. H. Reaney, R. M. Wilson - Google Books

http://books.google.de/books?id=fPoujUPs3hYC&pg=RA1-PA13&dq=April++name++etymology+ancestry&lr=&as_brr=3

This classic dictionary answers questions such as these and explains the origins of over 16,000 names in current English use. It will be a source of fascination to everyone with an interest in names and their history.