What we do is have SQL Server manage the identity ranges for most of our tables. If you go to publication properties, Articles tab, then click on the ... for the table, there will be a tab for identity range. You can set the range for publisher vs subscriber. For example. 1-10000 publisher, 10001-20000 subscriber, and new ranges will be allocated when they reach the threshold percentage.
Otherwise you can reseed the subscriber manually, if you can make sure that they won't conflict, like picking a large seed, say 1 billion. Or you can set up even numbers on one server and odd on another, or positive on one server and negative on the pocket PC.
SQL Server DBA