Yes, you can do both.
Replication from 2000 to 2005 works fine, but it can be a bit trickier to set up. I have found it easiest to configure the publication from Enterprise Manager on the SQL 2000 side and then configure your subscriber using Management studio.
NTEXT can be replicated, but it slows things down significantly. Try to avoid them if possible (perhaps you do not need them on the subscriber). You could also replicate everything but the NTEXT columns and synchronize these fields in another way.