Dear All, the new versions of inkscape (0.47 and 0.48) are not able to edit graphic postscript files to add tags for psfrag.
It seems that inkscape developers are working on this issue.
(http://tex.stackexchange.com/questio...ing-for-psfrag), but for the time being the problem is still there.

Can you recommend any other Ubuntu software for this purpose?
On the web there are some workarounds, but they are somewhat cumbersome.

Thanks,
Ettore