There are a lot of nice hiking trails in the Austin area, many of them discussed in Tom Taylor's book 60 Hikes within 60 Miles: Austin and San Antonio.

Other sources of hikes are:

• Local Hikes website
• Trails.com -- (fee based site) w/ geocaching links

There is also a Scout (Capital Area Council) patch for hiking around Austin:

• Texas Heritage Trail

The Texas Heritage Trail is part of a national collection of historical and heritage trails -- 13 in Texas -- which were largely established and documented by local Scout councils:

• Nationally Approved Historic Trails