Get User Profile Properties by Using SharePoint UserProfileService.asmx Web Services
The following code snippets will get the user profiles properties both OOB and Custom:
Profiles.UserProfileService UPS = new Profiles.UserProfileService();
UPS.Credentials = System.Net.CredentialCache.DefaultNetworkCredentials;
UPS.PreAuthenticate = true;
PropertyData custom = UPS.GetUserPropertyByAccountName("domain\\FirstName.LastName", "CustomID");
string val = Custom.Values[0].Value.ToString();