In Origin 7 there is a transpose command at the bottom of the Edit menu that will do what you want. I think it's also there in Origin 6.1, but if it isn't you might try converting to a matrix, transposing the matrix and converting back to a worksheet.
...You want to do it in LabTalk. Certainly there are commands available for the second method. If Transpose is available on your Edit menu you can also find its menu ID (Ctrl+Shift+Transpose will type it to the script window) and execute it with
(You can find other useful actions like this -- hold down CTRL and SHIFT when you click on edit:transpose and in the script window you will get a response Menu id=36466. To do the same action with labtalk use the 'domenu' command. This works for most menu items.)