So I could be wrong, but I've heard most lenders are very weary of lending for a condo, and typically want a very large percentage down. One of my buddies owns a condo unit and he said it's a pain in the ass for him to sell them because of this.
As for other advice, I'd say be prepared to take on all the new bills. Not sure what you currently pay for, but if it's just electricity, all of sudden you'll get water/sewer, garbage, and perhaps natural gas slapped on. Probably equates to $80-120ish for most people so its not a huge amount, but it is something to keep in mind. Also, be ready for unexpected expenses. No more calling the landlord if your refrigerator breaks, heater stops working, etc.
Lastly, and this is just my opinion...but if you find the perfect house for you but can't afford the 20% down, don't be afraid of the PMI costs. Yes, paying for PMI sucks, but if you end up skipping that house and end up settling on a less attractive one, that will always eat at you. Besides, it's not THAT expensive...most people get 20% equity within 4-5 years, if not sooner.