well I don't know exactly (don't have exell) but something like this should work:

cut and past the column into an new file, on the first cel of the column next to it you put an ; then you drag the little black squer (right under) untill the last row example of result:

column1 column2
mailadres1 ;
mailadres2 ;
mailadres3 ;

now select both columns and past the into notepad (or something like that)
remove the enters and put the line in the bcc line of outlook (or some other program)