WordPress MU

Well after some analysis... i resolved i need to change some of the default URLs provided by WPMU.
And i need your opinion about the best way to do this.
Why i need this?

1) For strong SEO porposes, cause my site is in spanish.
2) To make it look more tidy and understandable to non english audiences.

For example: i need this:
today: site.com/wp-login
tomorrow! :): site.com/conectarse
today site.com/wp-admin
tomorrow! :): site.com/admin
any clue?
htacccess? mmmm How?
Code? ouch!! it hurts.. but possible.
What´s your opinion?

Thanks a lot in advance!
Enrique