Ah yes, I was mistaken, iCal will only send invitations via Mail.app. Don't think you can change it. This was from the iCal Help "If you’ve set up Mac OS X Mail, you can use it to invite people to an iCal event."
You'll have to purchase the upgrade to either 10.4 (aka Tiger) or 10.5 (aka Leopard). I believe one can upgrade straight to 10.5 from 10.3. Either way, once upgraded, you can do Software updates to get it to the correct version.
HTH!
I believe iCal will use the default mail client whichever that maybe. I used to Eudora and everything automatically linked to it be it from the browser or any other programs that needed to send emails.
Careful when deleting the account from Mail.app. Unlike some other mail clients that will leave the messages alone. Mail.app will delete all messages assoicated with this account.
Hmm, that's not a lot of information. Are you getting an IP address? Check Systeme Preferences--> Network. what IP are you getting under the Airport? It should be a private IP like 192.168.x.y or at 10.x.y.z.
Also, in Advance..., check the DNS tab. what does it have?
Kay
Eset NOD32 would be my choice over BitDefender. Both of these update the virus definitions when available as opposed to a pre-set schedule, but NOD32 is lighter resource-wise.