I just did this yesterday, and you can do it. Order the SSD drive from OWC (macsales). You'll need to check "about this mac" - "system report" - "hardware" - "SATA/SATA Express" and then look at the right hand pane. Under "Apple HDD" heading you will see an entry for "bay" - if it's "lower" it means the 1 TB drive is located on the bottom of the mac as it sits normally, and you will order the data doubler kit along with the SSD drive. That kit includes a bracket for putting the drive in the upper bay along with some screwdriver, torx and pry tool. (NOTE: I went and bought a kit from iFixit afterwards because you really, really need that spudger).
OWC has online videos to walk you through everything. They also send you a paper instruction sheet, and you can watch the video while doing the work if you have tv/phone/another device that can youtube.
I found the process quite simple with all the directions. There are some connectors that you can break if you pull on them wrong, but the video/print docs point out to be careful you're not prying the socket off the board. And the little wireless antenna connector was hard to put back on because it was so tiny -if I'd only had the spudger ...
I installed the new drive, booted the computer, ran disk utility from the old drive to format the new one into one partition, then booted again into recovery partition, connected to wifi, and selected "install OS" on the new drive. It asked me to verify my apple id, then downloaded and installed Mavericks on the SSD. Then I migrated the OS to the new drive. Main thing - be sure you know the network password when you boot in recovery mode because it won't be stored in the settings any more.
At that point, I shrank the 1 TB drive down and made a second partition, and once I move all the data off the one partition I'll delete the OS off the old drive. Doing this, let me keep the SSD without making a fusion drive of it.
If you aren't comfortable taking things apart, there are surely apple certified repair shops who will do this for you. OWC might have a name. But if you want to give it a try, the documentation really is good.