Windows API function NetServerEnum called with SV_TYPE_SQLSERVER parameter returns all available SQL servers.

DECLARE INTEGER NetServerEnum IN netapi32;
	INTEGER servername, INTEGER level,;
	INTEGER @bufptr, INTEGER prefmaxlen,;
	INTEGER @entriesread, INTEGER @totalentries,;
	INTEGER servertype, INTEGER domain,;
	INTEGER resume_handle

MSDN link:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/netmgmt/netmgmt/netserverenum.asp

Visual FoxPro code sample (members area)
http://www.news2news.com/vfp/?example=165&function=252