One little thing to stress, included in audiogeek's great article, is the importance of a Hi-Z or Hi-impedance input for you so you can plug the semi-acoustic straight in without an extra preamp or DI box. Most of the decent interfaces have it now, either dedicated or a shared 'line' input with a switch.
Although if it's a high quality solid timber guitar you might want to aid the tone by investing in a dedicated guitar preamp to go between the guitar and the interface. But for a cheap Yamaha or other plywood guitar, the built-in pre in an interface will still be clean and pretty neutral sounding.
Here's a good link to 25 acoustic preamps, with links to manufacturers and user reviews:
http://www.guitarnot.../preamps1.shtml