Home server WP issues (mostly FTP related)

I have been slamming my head on my desk about this for far too long. I like to try and figure things out for myself but after two weeks of restarting again and again after I destroy something I’ve decided to ask.

Here’s how it starts.
-Ubuntu server 10.04 install, fresh with nothing but OpenSSH installed.
-update/upgrades done
-Lamp-server^ installed
-database configuration goes smoothly
-latest.tar.gz downloaded, configured contents moved to /var/www
-install.php runs fine
-website looks fine and I’m ready to start configuring.

Here’s where things go wrong. Any plugins, templates, widgets I try to install it asks for FTP access.
-install vsftpd
I’m lost. I’ve been googling FTP permissions for two weeks now and nothing seems to be giving me the right instructions.

What I want to do is give the username “greg” read/write access to /var/www without breaking it.
The last time I tried the chown command I lost permissions just to view the site from a web browser and couldn’t seem to get them back.

This actually started the instant I switched from 3.2.1. I didn’t jump on the issue right away because it was just a home server that doesn’t serve much of a purpose other than a learning tool when I feel like playing around.

I’m assuming I’m only missing one or two steps in giving permissions to “greg” to access /var/www

Any help would be appreciated.
Thank you.