To call a webpage or webservice from stored procedure

First of all run following queries with sys admin rights:
sp_configure 'show advanced options', 1
GO
RECONFIGURE;
GO
sp_configure 'Ole Automation Procedures', 1
GO
RECONFIGURE;
GO
sp_configure 'show advanced options', 1
GO
RECONFIGURE;

After successful call then run following query:
Declare @Object as Int;
Declare @ResponseText as Varchar(8000);

Exec sp_OACreate 'MSXML2.XMLHTTP', @Object OUT;
Exec sp_OAMethod @Object, 'open', NULL, 'get',
                 'http://[domain name]/abc.aspx', --Your Web Service Url (invoked)
                 'false'
Exec sp_OAMethod @Object, 'send'
Exec sp_OAMethod @Object, 'responseText', @ResponseText OUTPUT

Select @ResponseText

Exec sp_OADestroy @Object