we've been thinking about this too ... DS will be about 21 months old when ziggy arrives... and I'll be recovering from a c-section so picking him up and carrying him around without help will be difficult (or out of the question) for a little while ...

our plans so far include:-

1. move DS to his new room and single bed in the next couple of months, so it's not associated with ziggy's arrival
2. having a prezzie for DS to give ziggy, and a prezzie ready and waiting for ziggy to "give" DS
3. possibly having a "baby" for DS to practice with. So mummy has a baby, and he has one too.
4. if he's showing any signs of readiness, starting to TT DS before ziggy's entrance.
5. we've ordered a book called "My New Baby" by Anie Kubler - check it out

but am loving getting more ideas