* Senate rejects Republican spending freeze attempt

* Republicans in House offer plan with tax, spending cuts

* McCain to offer alternative budget plan in Senate

By Jeremy Pelofsky and Richard Cowan

WASHINGTON, April 1 (Reuters) - U.S. Senate Democrats on Wednesday rejected a bid to freeze some government spending as House Republicans offered an alternative budget plan that would slash taxes and repeal most stimulus spending.

The two chambers of the Democratic-led Congress were moving toward passing as early as Thursday slightly slimmed-down versions of President Barack Obama's $3.55 trillion 2010 budget plan.

Since Democrats have comfortable margins in the House of Representatives and Senate, the House Republican plan is not expected to pass. The budget legislation is not binding but sets guidelines for spending and tax measures Congress will consider later this year.

The top Republican on the House Budget Committee said his party's 10-year plan would begin to reverse rising government outlays by repealing most economic stimulus spending starting next year. He also proposed large corporate and individual tax cuts.

"It is very important to understand, we are going into an ocean of red ink in this country. We cannot go down this path of borrowing and borrowing and borrowing," Representative Paul Ryan told reporters.