n97geeks posted a nice video:

Testing the durability and scratch resistance of the N97. It holds up surprisingly well. More Nokia N97 at www.n97geeks.com

This website allows Zain customers to manage their MMS inbox.
If you have received a message asking you to visit this page, it is because you have not yet registered for Zain’s MMS service or your mobile phaone is not yet configured to receive MMS.
If you want to view/retrieve/manage your MMS, please go to http://legacy.kw.zain.com. This [...]

To send an International MMS, please refer to http://www.movistar.com.ar/servicios/mms_internacionales_gsm.html
The above screenshot, I gotten from the Google cache. I just can’t locate the existing http://mms.movistar.com.ar. If you know the current MMS retrieval for Movistar Argentina, please let me know.
Quote from Wikipedia:

Movistar is a major mobile phone operator owned by Telefónica Móviles. It operates in Spain and in many Latin [...]

When you click http://mms.nextel.com.ar, you’ll be forwarded to the NII website which is http://216.194.142.201/services/niiar/anonlogin
In order to view the MMS message, you need to provide the login, phone number and password. Failure to provide any of these requirement, you won’t be able to view.
Quoted from Wikipedia:
NII Holdings Inc. (formerly known as Nextel International) is a mobile [...]

GPRS and MMS configuration for CTI Argentina
CTI GPRS
APN (Access Point or Network Access Point Network): wap.ctimovil.com.ar
Username: ctigprs
Password: ctigprs999 or white depending on the mood of the server
IP: 170,051,255,240
Proxy (only if requested by the phone to connect): 8080
CTI MMS (multimedia messages):
APN (Access Point or Network Access Point Network): mms.ctimovil.com.ar
Username: ctimms
Password: ctimms999 or white depending on the [...]

WebI
If you’re looking for a MMS setting and configuration, refer below:

Web (Basic function of your browser and connection to the data network):
APN: int.movilnet.com.ve (login and pasword blank)
MMS Settings:
APN: mm.movilnet.com.ve
IP and DNS: none
Use proxy: yes:
Proxy Address: 192,168,016,012;
Port Number: 8080
The multimedia server address is:
http://mm2.movilnet.com.ve/servlets/mms
WAP:
APN: app.movilnet.com.ve
IP address and DNS: nothing
PAP Authentication
Use proxy: yes
Proxy Address: 192,168,201,170 [...]

I didn’t manage to access http://mms.entelpcs.cl site. It gave me an error:

If you have reached this page, you will most likely be because you are using an outdated browser. We recommend you upgrade to an uneven version of Internet Explorer or Netscape Communicator. If you search for site www.entelpcs.cl click here
If you search the site [...]

If you accessing http://mmsaccess.vodafone.ro, you’ll be welcomed with:

This service allows you to view multimedia messages (MMS) that have been sent to you. For every message you receive, you can reply with your own multimedia message, or forward it to someone else.

Multimedia Messages can be sent by people with camera-equipped mobile phones and may contain pictures, [...]

absolon3 posted a nice video:

This is a video going over certain elements of features that I use with my N97.

Kindly refer to the below setting for the MMS configuration:
Movistar WAP (WAP GPRS)
Homepage: http://movistar.com.mx}
Tipo de servicio 1:wap
Gateway IP 1:10.2.20.1
Gateway IP 2:10.2.20.2
Port 1:9201(default)
Port 2:9201(default)
Timeout: 15 minutes
Speed (bps): 9600 default
Line Type 1 (linea 1):ISDN
Line Type 2(Linea 2):ISDN
GPRS APN: wap.movistar.mx
User Name: movistar
Password: movistar
Mensajes Multimedia (MMS GPRS)
Homepage:http://mms.movistar.mx
Gateway IP 1:10.2.20.1
Gateway IP 2:10.2.20.2
Port 1:9201
Port 2:9201
Timeout: 15 mins
Speed (bps):9600
Line Type 1:ISDN
Line Type [...]