Here's another great Morningstar post on useful URLs, written by jdmartin ( El Toro).
General interest websites

MFEA's getting started basics
MFEA's investor library
Vanguard's Plain Talk library catalog
Investment glossary
Social Security Administration
Social Security benefits calculator
401Kafe.com
403Bwise.com
Thrift Savings Plan for Federal Govt. employees
457 retirement plans for public-service employees
Wills & Trusts

Tax related information

Tax burdens by state
Estate taxes levied by States
State-by-State individual tax rates
State-by-State sales tax rates
IRS Tax Publications
Federal Income tax estimator
Marginal Federal tax rate table
Federal & state tax forms & publications
Tax Guide for investors
Capital gains tax planning
Wash sale tax rule
Complete online Resource for tax information
U.S. Treasury I-Bond tax reporting guide

Asset Allocation & Goal planners

SmartMoney's asset allocation planner
Vanguard's Online Investment Planner
Fidelity's Asset Allocation Planner
Mormingstar's Goal Planner.

Mutual fund investing

Mutual Fund Education Alliance
Investment Company Institute
ScottBurns.com
Coffeehouseinvestor.com
Standard&Poors Index Services
iShares Exchange Traded funds
Real Estate Investment Trusts
Case study on portfolio rebalancing

Portfolio analysis tools

Morningstar Fund selector
Morningstar Fund compare
Morningstar Instant X-ray
Morningstar Quotes & Quicktakes
T. Rowe Price stock overlap & portfolio analyzer
Fidelity Fund Evaluator
SmartMoney Mutual fund analyzer
SmartMoney Fund finder

Bond fund investing

The Bond Market Association
Federal Reserve saving Bond Wizard
BondResources educational library
I-Bond Tutorial
Inflation-Indexed Securities

Historic data, risk analysis & charting

Callan Associates' historic Asset class Rates of Return data
Historic returns
Federal Reserve historic rate data
Historic inflation data
RiskGrades.com Measurement tools
S&P/BARRA charting
S&P/BARRA historic sector weightings
S&P/BARRA historic sector weights by index
S&P/BARRA Monthly Returns
Financialweb's Historic price quotes
Yahoo's Historic price quotes


Funding educational expenses

Savingforcollege.com
Section 529 plans
Educational tax incentives
Making Sense of College Investment Options
Sue Stevens' comparative guide to college funding
College funding overview
Annual college costs
Section 529 plan vs. financial aid
Hope scholarship & lifetime learning credits
529 plans as estate planning tool

Insurance tools & rating services

Life insurance needs calculator
QuoteSmith.com quote service
Standard & Poor's rating service
A.M. Best rating service
States' Dept of Insurance
Insurance web learning center & toolbox
Article archive on Insurance
Comparative costs of Term vs. Permanent life insurance

Annuities

All about annuities
Section 1035 tax-free annuity exchange
Using annuities in Medicaid planning
SEC guide for variable annuities
Annuity payouts
Immediate annuity options & quotes
Annuity taxation
Making sense of Annuities

Long-Term Care provider & policy information

LTC Glossary
State-by-state average LTC costs
LTC insurance provider directory
LTC insurance library
Basics of LTC
LTC features & benefits
LTC policy riders
Customizing your LTC policy

See also John's Reverse Mortgages and Developing a long-term investment plan