I am getting a 2-year old Pomeranian tomorrow and don't like its name, but am also going to be working at introducing it to our 8-month old kitten. Any advice on if or when I should work at changing its name. After getting used to the kitten or right away?

As soon as you are with the dog, begin calling him by his new name. Say it often as you talk to him. Repeat it endlessly in conversation with others in his hearing. Pat him or hug him or touch him whenever you say his name.

What was his old name and what is the new name?

I'm not sure how to introduce a new dog to an established cat. One or more of the dog experts who have cats will stop by to help you with this. I do know you will want to give the cat lots of love and affection and attention so he doesn't think he's being displaced by the dog. You don't want the cat to be pooping and peeing in strange places out of jealousy. Both are young, so it probably won't be too difficult acclimating them to each other.

Hang in there. Our experts will drift over here.

Her old name is Tasha and I am thinking about changing it to Chloe. I have been reading up on how to introduce them but would take any advice I can get! Thanks for the info its very much appreciated!

If she already knows her name I would wait until the introductions are over.

It's going to be stressful enough getting her to behave around the cat, you don't want her confused with commands as well. If she is getting too pushy with the cat you need to be able to call her away.

Once that is done you can either re-train her straight up with the new name, or gradually morph it in to the new name.
If you decide to re-train it's just a matter of repeatedly using the new name and rewarding when she responds.
You can get her to sit and every time she looks away from you, say her name, get her attention and then give a treat.
Wait until she looks away again and repeat the process.

If you want to morph the name you can start calling her Tashie, putting more emphasis on the ee sound. Then once she's used to that, drop the Tash and start using Chloe (again, emphasis on the ee sound).