Important things to note in relation to using sharepoint out-of-box webservice locatate at http://servername.com/_vti_bin/lists.asmx.
1. A GetlistItems call only returns filled colums of the rows. So if you do not have any data in column “First Name” in row 6, the xml return data will have all columns for row 6 except for the attribute “Firstname”.
2. Data returned from GetlistItems return will only represent the paging limit set on the veiw in sharepoint. Thats to say, if item limit propertiy on the list view is set to 100, and you have 1000 data in your list, the data returned by GetlistItems when no rowlimit parameter is set will equal 100 and not 1000. To get all the data (1000), either set the rowlimit to 1000 or more when calling GetlistItems or set the item limit property of the default list view on the Sharepoint site.