Back in the old days, I use to create multiple versions of videos for upload at Blip.tv for different users on dial-up, DSL and Broadband. There came a time when everything was being rendered as Flash video so I got lazy and just uploaded .wmv videos.
Things have changed. Again. No sweat, this can be worked out. These are the specs that I nabbed from the Blip.tv How Should I Export Videos. Your video editing program may or may not do this for you so check that out before you invest cash money into buying a video editing or conversion program.
For those of you on Windows Movie Maker or Windows Live Movie Maker you can't export to the QuickTime format. This is like inviting the Hatfields and McCoys to a Sunday dinner. Ain't gonna happen. Jump down to conversion options for more info.
If you are recording video with a standard definition camcorder the suggested frame size is 720 x 480. This is also true if you are using the free/limited upload account.
In your video editing program you'll need to make sure that you are exporting the video out at that size.
If you have a paid Blip Pro account you can upload a 1280 x 720 sized video and also have a HD version of the the video as well.
H.264 in your video editor it might say mp4, mov or something in that neighborhood but it does need to be compatible with the QuickTime video format.
If you have the free QuickTime player try to open with that program. If it won't open the mp4 then it isn't QuickTime compatible.
AAC if you select the QuickTime export this will be selected for you.
Video Bit Rate
3.5Mbps - 5.0Mbps
Audio Bit Rate
Fast Start Enabled
If you have a copy of QuickTime Pro this will go a lot easier on you. $29.99 and you will be able to export to .mov and the iPhone/iPad format. This will work with most version of .avi and .mov videos.
It will not, I repeat, will not work with .wmv content. You'll need to convert .wmv videos to .avi
Another option that you have is Miro Video Converter which can save in a Quicktime compatible .mp4 or iPad version. This is drag and drop conversion so you will have to figure out which one of the pre-sets gets you are close as possible to the above specs.
And I have to mention old faithful, MPEG Streamclip. It can't do .wmv but it can dang near do just about everything else.
If you do all of the above Blip.tv will be happy to upload your video. If not you will get six e-mails in your inbox telling you it isn't going to happen.