I used Crucial's Ram to upgrade memory on my Acer 3680 from 512MB to 1536 MB. I ordered the Ram using this link. It arrived in 6 days thru UPS and USPS. I had to struggle to identify how to open the laptop to upgrade, but found handy help at another blog.
Acer's own website does not provide much information on how to upgrade their laptops with such minor improvements. Dell is much better that way.