Hi
though I do not know Act I would assume that this program at least is
able to read comma separated files. So save your Excel file as *.csv
file ans try to import this in Act. At least Act can export to Excel so
I would assume the other way around nshould be possible as well.
Also you may ask this question in the Act user groups (e.g.
http://www.act.com/community/usergroups)