I'm looking for some expert (or at least experienced) opinions:

What're some efficient ways to transfer files from one system to another via the internet?

Both users know each other's public IP addr and they have DSL with a NAT firewall. They want to share files.

1. What if both users have Windows (2000, XP, ME...)?

2. What if cross-platform (Mac, Linux, Windows)?

Using Gnutella/LimeWire you can get the job done (even cross-platform) with Direct Connect... but are there some other better alternatives? Are we cracking eggs with a hammer here? (POP mail DL at 160KB/sec, Gnutella DL at 12KB/sec-20KB/sec... no joy!)

Concerns: Ease of use. Performance. Reliability. User monitoring, control, security...

Assumptions: Users want to share some BIG files (50MB-750MB) from time to time, but mostly within just a small group of users.

Average volume = 10-100MB per day, up to max 500MB per day. Low-cost solution using existing DSL. Email is not a good solution.

Please make some suggestions... thanks!

__________________
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