Q: How do I put short videos taken with my iPhone 4S on Photo
Stream so I can access them on my iPad 2?
A: Unfortunately, the iCloud Photo Stream feature only provides the ability to upload and synchronize photos between devices, not videos.
Although not as seamless as the iCloud Photo Stream, which automatically uploads photos in the background, it is possible to work around this to some degree using third-party software apps and services. YouTube and Vimeo, for instance, can host your videos privately and allow you to view them from the respective apps on your iPad or within the Safari web browser. Videos can even be uploaded to YouTube directly from the iOS Photos app, eliminating the need for an additional app.
Further, the more generic cloud file storage service Dropbox can provide you with a free 2GB account that you can use to store videos, and the Dropbox iOS app can automatically upload any new videos it finds in your Camera Roll as soon as you open the app.
Note that it appears that iOS 7, which will likely be available in the next few weeks, will introduce video support in Shared Photo Streams, however there are no indications that video support is being added to the main Photo Stream feature, so this will still require you to create a shared photo stream and manually add any videos that you want to share.