I've been out at Bijou Park and down into the meadow/golf course below a few times and for me as a newbie it has been a great place to start getting comfortable with XC gear. Mostly flat, and seems a fair amount of folks XC ski there, so there are lots of (classic) tracks available if that's what you want.
Also, a couple miles up Hwy 89 towards North Shore from "The Y" there's wooded National Forest land on the left that's mostly flat but eventually leads into some hills, then a little further on there's Camp Richardson, which has a set of maintained XC trails and reasonable fees. And a little further up from that off Fallen Leaf Road (on the way to Fallen Leaf Lake) people XC ski in the woods and meadows there (free, not maintained).
As a really nice bonus Lake Tahoe Community College is just about to open a new Nordic Center! Haven't seen it yet, but I've been told it will run somewhat parallel to Al Tahoe Blvd between the back side of the College and Trout Creek from the Post Office end almost down to Pioneer Trail. Here's a blurb from a recent Facebook Posting...
LTCC Nordic Center plans to open FRIDAY, March 1st. With the goal in mind of offering the best quality skiing experience, we believe an additional two weeks of winter will potentially provide improved conditions.Season pass sales are available FRIDAY, FEB 8th. The 2013 Season Pass prices are: $49 family passes, $39 couples pass, $29 individual pass, $5 day use fee, $10 LTCC or LTUSD enrolled student pass, $100 business pass. There will be both a skate skiing and a classic option on the same course.
They don't seem to have a dedicated web site for the Nordic Center, but you can get to more information here.
Lots of good options for XC skiing right in South Lake Tahoe, and as mentioned in a previous post there's also Hope Valley roughly at the intersection of Hwy 89 and 88 (~30 minutes from SLT on the way to Kirkwood).