Dictionaries - Online and iPhone
There are some fabulous tools out there to help you read Japanese faster, learning characters along the way and allowing you to exeprience the real Japanese internet!
Browsing Rule #1
Use Firefox for your browsing. There are ton of add-ons for Firefox that are free and easy to use. You can download Firefox for free from www.firefox.com.
There are several glossing tools for Japanese, but I like this one the best. It's quick and easy and doesn't get in the way when you are trying to focus on reading content. Make sure to read the installation instructions carefully, you'll need to go to a second site to get the Rikai-chan dictionary. Both are easy to install from within Firefox.
Online Dictionaries
My favorite is always Jim Breen's WWWJDICT. His Word Search feature is a straight up dictionary. But the Translate Words feature is also handy. Copy/paste a block of text and it will produce a vocabulary list for you to reference as you read the text. His site also allows you to look up characters by radical or stroke count, but it's a bit cumbersome to use. Be sure to check out his Browser Buttons for easy integration into your web browser.
iPhone/iTouch dictionary
There are several options for Japanese dictionaries on the iPhone/iTouch, and probably more coming out all the time. There is a nice free application, called wwwJDict, that is an iPhone/iTouch interface to Jim Breen's online WWWJDICT. But you have to be online to use it, and it can be quite slow if you are on the EDGE network.
Personally, I like Kotoba!, a free dictionary that is downloaded to your iPhone/iTouch, so you can use it anytime. It's a 62MB download, so if your iPhone/iTouch is full you may not want to get it right away. But if you've got space, it's a fabulous application! The kanji entries even include stroke order animations from KanjiCafe.com.
Combine Kotoba! with the iPhone/iTouch's Handwriting input for Chinese and you have a mobile kanji dictionary that you can draw characters into for searching!
On your iPhone/iTouch, go to Settings > General > Keyboards > International Keyboards > Chinese (Traditional) and turn on the Handwriting keyboard.
To use the handwriting keyboard with Kotoba!, tap the search field to open the input pane and tap on the globe icon next to your space bar to switch input keyboards until you get the Chinese handwriting pane. In the open box that is presented, use your finger to draw a character. Tap the blue button twice to complete your search in the Kotoba! dictionary.