I'm afraid down-grading between releases is really quite awkward to do without breaking things.
From an Ubuntu 10.04 system there should be no reason to "upgrade" to 10.04.1 as simply applying the normal updates will result in a 10.04.1 system anyway.
Personally, if you are not experiencing any particular issues with the 10.10 dev. release, I would stick with it. 10.10 will be released soon anyway. If you are not experiencing any issues, perhaps avoiding updates for the time being would be best.