I guess what I'm trying to say is; maybe, maybe not. Depending on your service provider, you should be able to view and respond to MMS on the N900. I do every day with my N810.

My cell phone is company provided. It has a 2 inch screen. I receive MMS from within the company sent to my telephonenumber@serviceprovidor.com. I also have these messages forwarded to my Gmail account and I read and respond to them using my tablet. Since my provider detects that my Gmail account is not an MMS capable phone it will attach the following to the message:

The words "VIEW" and "REPLY" are links to my providers web service where I can ...wait for it...
View and reply to an MMS message sent to my phone using my N810's web browser and keyboard instead of my tiny phone screen with T9 predictive text.

Most carriers (at least in North America) have similar set-ups.

Now the question is does SMS on the N900 support links in messages?

If not, set up a Gmail account and have them forwarded.

Also any e-mail with attached images sent to my SMS gateway number is considered MMS.

Most Providers list this gateway number so if someone you know has a MMS phone and you want to send them a pic or animated gif of Santa lighting up Rudolf's nose you can from your N900's e-mail app. In most cases all you need to know is the service provider and their phone number.

Regard, a list of service providors SMS gateway's >> http://basicstate.com/htm/page.htm

Hmmm... the only problem I see with that is that I'm tied into my carrier, and they aren't going to be told that I am changing to a sim-free. They certainly won't have any support for it. If I can adjust setting easily myself (I worked out yesterday how to set up SMS noficiations for voicemail) that will be fine. If not, I may end up with some poor cutomer support girl struggling to understand what I'm asking for.

But thank you. If that will work (and trying it is the only way to find out) it will solve my problem.

NP...
Yes, the proof in the pudding is in the tasting isn't it?
I am very confident that you will be able to set up a solution on your carrier using just what we know now. In fact I will volunteer to help you out with the details. When it is all said and done I think you will find that viewing, replying, and sending MMS on the N900 turns out to be a non-issue.

You can start now by asking your carrier if you can forward or c/c all SMS sent to your phone number to an e-mail account. . Your carrier may even provide a web interface where you can change SMS options on your account from their web site.

When we do find and set up the procedure for your service provider will you be up for writing a WiKi entry to help others?

I'll help with the details.

Sounds like a good project.

I was actually thinking of a small wiki of my own on the "Bear's Guides" model, explaining the very simple to the very simple. I'm am certainly up for helping with the wiki page. I have collected a pile of links and vids which would be useful in one place.

That's the spirit... It doesn't matter where as long as there is a record of what works. For duty and humanity... and all that.