Where to take your baby potty depends on your own comfort level and your baby's age. For young, exclusively breastfed babies, the bathroom sink can be a great option. Simply hold your baby over the sink, and after she's finished going, rinse it all down the drain. Some people might be uncomfortable doing that, but like George Costanza said, "It's all pipes!"
As your baby grows, a potty is a great option, though with that comes a bit more work, with emptying and cleaning it. But still, it's much easier to rinse a potty than to clean a baby who's just pooped in her diaper. I love the Baby Bjorn Little Potty style potties, pictured below.
We found a knock off at Target in California in 2006, but we haven't found them since. It was called a Bebe Jou. They both have all the same features. The main thing to look for in a potty is stability, which is why these potties are so great. The splash guard is also very helpful for boys when peeing.
My husband and first born, using the Bebe Jou.
When out and about, I recommend the Potty On The Go. For a more in depth review, click here.
Transitioning to the toilet is made much easier with a toilet seat insert. Get one that's nice and padded, but without handles so that it fits in a diaper bag for those times when you're at someone else's house or in a public restroom.
The transition to toilet is fun because then you just flush the poop away. I start the transition at about 5 or 6 months, when the solids start getting introduced, which is when poop starts to really get gross. It's so nice to have a baby poop in the toilet, and not all over themselves. Sometime after your baby turns into a toddler, you can forego the insert and just let them sit on the toilet. For my son, it was easiest for him to climb onto the toilet and sit there facing the tank rather than the usual way. As always, do whatever works for you.