Hello and welcome! Sorry that you're here though...UC isn't fun!
A great website to learn about the different medication options for UC is the Crohn's and Colitis Foundation of America website (www.ccfa.org). I did a ton of reading just after I was diagnosed, as knowing as much as I can helped me come to terms with having this disease. I guess I am fearful of things that I don't understand!
How extensive is your UC? Did you have the c-scope before or after starting on the Asacol and Canasa? Are things continuing to improve, or have you kind of stalled out on improvement? If so, you may want to consider upping your Asacol doseage up to 12 pills daily (of course, consult your GI about this). You may also want to switch to a mesalamine enema instead of the suppository, as the enemas reach further into the colon.
Hope that you get better soon!
Status: Remission since May 2009!
Symptoms began in November 2008, ~4 weeks after giving birth to my son.
Diagnosed with pancolitis on 1/30/09
Currently taking Apriso (4 0.375g pills ONCE!! daily), mesalamine enema twice weekly, Natural Factors Ultimate probiotic 12/12 Formula, and Zoloft (25 mg).