Copy Command out of memory

I was trying to run a bulk data load using the COPY command on PGSQL 8.1.0.

After loading about 3,500,000 records it ran out of memory - I am
assuming because it ran out of space to store such a large transaction.
Does the COPY command offer a similar feature to Oracle's SQL*Loader
where you can specify the number of records to load between commit
statements, or will I have to break the file I am loading into smaller
files?

Or can a transaction be bypassed altogether with the COPY command since
any failure (the load is going to an empty table) could easily be solved
with  a reload of the data anyway.

Thanks,

Kevin