If you've just started I2P, the Active: numbers on the left should start to grow over the next few minutes and you'll see a "shared clients" local destination listed on the left (if not, see below). Once those show up, you can:
* blog anonymously - check out Syndie
* chat anonymously - fire up your own IRC client and connect to the server at localhost port 6668. This points at one of two anonymously hosted IRC servers, but neither you nor they know where the other is.
* browse "eepsites" - on I2P there are anonymously hosted websites - tell your browser to use the HTTP proxy at localhost port 4444, then browse to an eepsite -
o orion.i2p: a site which tracks eepsite uptime and changes
o inproxy.tino.i2p: a site which tracks active eepsites
o forum.i2p: a secure and anonymous connection to forum.i2p.net
o www.i2p: a secure and anonymous connection to www.i2p.net
o eepsites.i2p: an anonymously hosted search engine of eepsites
o ugha.i2p: ugha's eepsite, a wiki that anyone can edit, and lots of links
o dev.i2p: a secure and anonymous connection to dev.i2p.net
o Freenet proxy: fproxy.tino.i2p
There are many more eepsites - just follow the links from the ones you see, bookmark your favorites, and visit them often!
* browse the web - there is currently an HTTP "outproxy" in I2P hooked up to your own HTTP proxy on port 4444 - simply set your browser's proxy to use it (as above) and go to any normal URL - your requests will be bounced through the I2P network.
* transfer files - there is an integrated port of the Snark BitTorrent client.
* use anonymous email - postman has created a mail system compatible with normal mail clients (POP3 / SMTP) that allows email within I2P as well as mail from and to the normal internet! get your account at hq.postman.i2p. We bundle Susi's susimail, a web based anonymity-oriented pop3/smtp client configured to access postman's mail services.
* and lots more