Convert CCK text field to integer

Hi,

is there a non-programmatic way (meaning: a working module or a way that does not require writing code) that allows to migrate CCK fields between field types?

Example: I have a text field that stores (mostly) numeric values (e.g. 320 g); now I have to perform calculations with those values and thus need a more precise field type like integer. Ideally this "field type migrator" would allow me to discard all illegal values (i.e. the "g").

Is there something like this already available?

Thanks & greetings, -asb

PS: I'm also looking for a way to move/migrate data from certain CCK fields into Drupal core's taxonomy. Again, the real-world logic would be trivial: Look in a given CCK field, select a vocabulary and create a new term for every value from the CCK field that does not exist yet in the vocabulary. Again, as it seems, Drupal's data model makes this complicated... Or are there any solutions for this?