Hi Melissa,
You can do this by using CSS. You can float the form field divs left:
.form-design-field { float: left; }
And then set the widths of the fields:
input[type="text"], textarea, select { width: 250px !important; }
The overall width of the form section on your landing page will need to be wide enough to fit 2 columns or more if you want. You can also use javascript when needed to alter the CSS.
Cheers,
Ben