asp.net and html webservices ?

Hello,
i have an HTTP webservice that i would like to use with my asp,net project . i can control the webservice using http GET and POST . for examble , i want to send an sms message i use
http://some-url.com/service/sms.cgi?number=FROM&to=TO&message=MESSAGE

- my question how what should i do in asp.net so i can open the prevoius url and return result ?
- also , the webservice return results in TEXT and XML . what can i do in order to parase the XML ?

finally , what can i do so in case it faild to open the url it displays nothing , because the url will contain sensetave information

THANKS