First of all, let me say that there's absolutely no need to build your sprite-sheets manually. There are some very good tools for this purpose. Also exporting animations from Flash should be easy and straight-forward. Here's how you do it:

You can export your animations by selecting File > Export > Export Movie.... Then you select PNG Sequence as format and it will export to a series of PNG files.

Then you can head over to this question where you'll find lots of good answers on how to create sprite-sheets from these PNGs.

Flash CS6 will have a feature to directly export animations to sprite-sheets. Older versions will have to use the procedure outlined above.

First of all, let me say that there's absolutely no need to build your sprite-sheets manually. There are some very good tools for this purpose. Also exporting animations from Flash should be easy and straight-forward. Here's how you do it:

You can export your animations by selecting File > Export > Export Movie.... Then you select PNG Sequence as format and it will export to a series of PNG files.

Then you can head over to this question where you'll find lots of good answers on how to create sprite-sheets from these PNGs.

Flash CS6 will have a feature to directly export animations to sprite-sheets. Older versions will have to use the procedure outlined above.