Ford Motor Co. redesigned its Model T pickup trucks a lot between 1925 and 1927. In the end, the newer ones looked a lot like the older ones.
Same way with the IRS, which recently asked for public comment on its proposed new Form 1040 income tax form, pictured here. It looks remarkably like the 2008 version, pictured here. Mostly, some of the numbers, for standard deductions and the like, have been adjusted for inflation.
Some of your calculations may be way different, though, because of all the economic stimulus changes that are kicking in. You should eyeball your tax situation, and specifically check what's being withheld from your pay stubs against the taxes you paid in 2008, to see if you are on track toward where you want to be at filing time.
And if numbers aren't your thing, try this.