Stevey, you worry too much…
Just go with the flow and see if you can sense when she might be interested in meeting you face to face. If I were her, I’d be most comfortable talking to someone online after emailing and chatting for at least of couple weeks, depending on how often we chatted. Don’t say anything about meeting until you’ve exchanged a few emails. If things are going well and she’s still interested in you, politely ask her if she would be interested in going somewhere to meet each other.
Yes, I would suggest you invite her to IM with you before meeting. I IMed with my boyfriend for a month before we ever met face to face.
The idea is that you want to make her feel as easy-going and comfortable with things as possible before moving forward. So to do that, you need to make yourself feel easy-going and comfortable. Try not to worry so much about every little detail and just let it be what it is. A woman is more likely to move forward with a man with whom she feels relaxed.