Hey, and welcome to the site.

Originally Posted by: Shyke
I would like to learn to play lead guitar. I play a bit but am not proficient at it.

I don't know exactly what your skill level is, so please don't take any of these suggestions the wrong way. If something is below your level, then feel free to skip it and move on until you get to where you are being challenged and learning new knowledge and skills. :)

Also, if you are completely unfamiliar with playing single note lines on the high thin strings, then you might find it useful to go all the way through the beginner courses. Some of the lessons listed below are part of the courses.

http://guitartricks.com/course.php?input=1
http://guitartricks.com/course.php?input=2

There you will find some of the below lessons in a wider context and get practice at playing simple single note melodies that can help your conceptual understanding of what a melody is and get practice at playing them.

Also, after those courses the rock, blues and country courses have lots of great info that can help you get moving toward playing leads.

GT Tutorials For Learning Lead

1. Understanding What Scales Are

Chord and Scale Relationships
http://guitartricks.com/tutorial.php?input=426

Using Scales to Connect Chords
http://guitartricks.com/tutorial.php?input=427
http://guitartricks.com/tutorial.php?input=428

Learning the Major Scale
Major Scale Patterns and Positions
http://guitartricks.com/tutorial.php?input=453

C Major Scale For Beginners
http://guitartricks.com/tutorial.php?input=473

C Major Scale Exercises For Beginners
http://guitartricks.com/tutorial.php?input=463

A Minor Scale for Beginners
http://guitartricks.com/tutorial.php?input=453

A Minor Scale Exercises For Beginners
http://www.guitartricks.com/tutorial.php?input=466

Major and Minor Scale Exercises
http://guitartricks.com/tutorial.php?input=451

2. Learning the basic mechanics of playing "licks"

Sound & Expression On Lead Guitar
http://www.guitartricks.com/tutorial.php?input=475

http://www.guitartricks.com/techniques.php
(Have a look at the page and take your time to tackle things like: pull-offs, hammer-ons, bending, alternate picking, muting, etc.)

3. Learning Pentatonic scales and starting to play some licks

Blues In E - Rhythm & Lead
http://www.guitartricks.com/tutorial.php?input=170

Pentatonic Minor Scale Exercise - All 5 Positions
http://www.guitartricks.com/tutorial.php?input=185

Pentatonic Scales & Frameworks
http://www.guitartricks.com/tutorial.php?input=296

Adding Major Notes to Pentatonic Minor
http://www.guitartricks.com/tutorial.php?input=217
http://www.guitartricks.com/tutorial.php?input=232
http://www.guitartricks.com/tutorial.php?input=244

Introduction to Improvisation (Major and Minor Scale)
http://www.guitartricks.com/tutorial.php?input=483
http://www.guitartricks.com/tutorial.php?input=491

4. Learning to see scales all over the fretboard

Modes Across the Fretboard (all the positions of the major scale)
http://guitartricks.com/tutorial.php?input=451

Visualizing Fretboard Scale Patterns
http://guitartricks.com/tutorial.php?input=419

Visualizing Chromatic Fretboard Scale Patterns
http://guitartricks.com/tutorial.php?input=462

Intro to Jazz Guitar & Improvisation
http://www.guitartricks.com/tutorial.php?input=519

And these are just the ones that I know about! There are lots more, feel free to ask the other instructors in their forum about playing lead from their perspective and lessons. After all that stuff you should also check out the links magicninja provided (Good job, thanks!). They are a useful way of viewing and using the site.

I wish you the best of success learning lead. Hope this helps, let us know how it goes for you! :)