I noticed you are having problems with Ustream.
What you need is some kinda software that can stream what is on your desktop live to Ustream. Your problem is the webcam is the only video feed in so it will only pick up you and your voice. With software that can stream your desktop, all you would have to do is connect to skype and put a video of you on your webcam on the desktop and accept your audio and you are done. This is what spoony does in his videos
http://www.justin.tv/spoonyone/b/266319465
Go to 53:00 in the video, he's talking to his friends on skype while playing the game and it's recording his voice. If you can find out what he's using (I don't know, sorry), that can be a very good start to figuring out your technical difficulties.
If you aren't hardcore about it being live, I do have some ideas.
I don't do live shows so I know nothing about that stuff but if I were to set up a podcast roundtable discussion. I would use skype and set my computer to record "what I hear" and my microphone at the same time. You might need to use some third party sound recorder (I have no idea of any free ones, I use the one that came with my movie software).
Once you have the show recorded, you can make it into an MP3 and upload it to Itunes.
If you want video with your podcast that is a little more tricky. I don't use skype that much but does it have a webcam roundtable chat feature? If it does then all you would need is Fraps (www.fraps.com, cost around $30). There is a free trail of fraps but it only allows 30 second recordings and it has a watermark on the video.
With Fraps you can record everything you see on your monitor. You will have to run the fraps footage through movie editing software to convert it into a mp4 or mpeg(wouldn't hurt to edit out the dead space too). You might want to record at half resolution too since the fraps avi files are huge on resolutions above 1280x1024.
You can then upload to blip.tv which doesn't have a 10 minute time limit like youtube.
If you still have your xbox360 and you are able to get footage from it, then you can use that to get audio using party chat. This might be the simplest way of doing things if you have the equipment. You don't even have to get the video, if you have a sound card that allows stereo in plugs then you can just plug the 360's audio jacks into it and record from there. Then convert the recording to mp3 and upload it.
Granted those last 3 options aren't "live" but I can only give advice on stuff I know about. I'd love to be on your podcast once you get the technical difficulties worked out and I feel better. Right now though I caught a cold and I have a soar throat so thinking and talking is a little difficult for me now.
One last bit of advice, don't get discouraged with this, once you overcome these problems, it'll be much easier and the show can be a fire and forget show with the only thing you have to worry about is what to say in it. I wish I could help you more with stuff but I have my own hurdles to deal with since I'm a noob who only started this year, I have a lot to learn myself when it comes to video/audio and software/hardware.