Listed below are links to the I.R.S. and all 50 State Department of Revenues:

Federal
1	Internal Revenue Service	http://www.irs.gov/
States
1	Alabama	http://www.revenue.alabama.gov/
2	Alaska	http://www.revenue.state.ak.us/
3	Arizona	http://www.azdor.gov/
4	Arkansas	http://www.dfa.arkansas.gov/
5	California	http://www.ftb.ca.gov/
6	Colorado	http://www.colorado.gov/revenue
7	Connecticut	http://www.ct.gov/
8	Delaware	http://revenue.delaware.gov/
9	Florida	http://dor.myflorida.com/dor/
10	Georgia	https://etax.dor.ga.gov/
11	Hawaii	http://www.state.hi.us/tax/
12	Idaho	http://tax.idaho.gov/
13	Illinois	http://www.revenue.state.il.us
14	Indiana	http://www.in.gov/dor/
15	Iowa	http://www.iowa.gov/tax/
16	Kansas	http://www.ksrevenue.org/
17	Kentucky	http://revenue.ky.gov/
18	Louisiana	http://rev.louisiana.gov/
19	Maine	http://www.state.me.us/revenue/
20	Maryland	http://www.comp.state.md.us/
21	Massachusetts	http://www.mass.gov/
22	Michigan	http://www.michigan.gov/treasury
23	Minnesota	http://taxes.state.mn.us/Pages/index.aspx
24	Mississippi	http://www.dor.ms.gov/
25	Missouri	http://dor.mo.gov/
26	Montana	http://revenue.mt.gov/default.mcpx
27	Nebraska	http://www.revenue.ne.gov/
28	Nevada	http://tax.state.nv.us/
29	New Hampshire	http://www.nh.gov/revenue/
30	New Jersey	http://www.state.nj.us/treasury/taxation/
31	New Mexico	http://www.tax.newmexico.gov/
32	New York	http://www.tax.ny.gov/
33	North Carolina	http://www.dornc.com/
34	North Dakota	http://www.nd.gov/tax/
35	Ohio	http://tax.ohio.gov/
36	Oklahoma	http://www.tax.ok.gov/
37	Oregon	http://www.oregon.gov/DOR/
38	Pennsylvania	http://www.revenue.state.pa.us
39	Rhode Island	http://www.tax.ri.gov/
40	South Carolina	http://www.sctax.org/default.htm
41	South Dakota	http://www.state.sd.us/drr2/
42	Tennessee	http://www.tn.gov/revenue/
43	Texas	http://www.window.state.tx.us/taxes/
44	Utah	http://www.tax.utah.gov/
45	Vermont	http://www.state.vt.us/tax/index.shtml
46	Virginia	http://www.tax.virginia.gov/
47	Washington	http://dor.wa.gov/
48	West Virginia	http://www.wvrevenue.gov/
49	Wisconsin	http://www.revenue.wi.gov/
50	Wyoming	http://revenue.state.wy.us/